Issue:
Bug: [REFACTOR]: Remove payment_method_id from RouterData struct



### Feature Description

This will remove the unused payment_method_id field from the Router_data, which is not at all used anywhere in our codebase, as we are storing the pm_id in payment_attempt.

### Possible Implementation

Removal of `payment_method_id` from the `RouterData` struct as whole and same for all the references of the struct.

### Have you spent some time checking if this feature request has been raised before?

- [X] I checked and didn't find a similar issue

### Have you read the Contributing Guidelines?

- [X] I have read the [Contributing Guidelines](https://github.com/juspay/hyperswitch/blob/main/docs/CONTRIBUTING.md)

### Are you willing to submit a PR?

Yes, I am willing to submit a PR!

Pull request description:
## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [ ] Bugfix
- [ ] New feature
- [ ] Enhancement
- [x] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description
<!-- Describe your changes in detail -->
This will remove the unused `payment_method_id` field from the Router_data, which is not at all used anywhere in our codebase, as we are storing the pm_id in `payment_attempt`.

### Additional Changes

- [ ] This PR modifies the API contract
- [ ] This PR modifies the database schema
- [ ] This PR modifies application configuration/environment variables

<!--
Provide links to the files with corresponding changes.

Following are the paths where you can find config files:
1. `config`
2. `crates/router/src/configs`
3. `loadtest/config`
-->


## Motivation and Context
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Why is this change required? What problem does it solve?
If it fixes an open issue, please link to the issue here.

If you don't have an issue, we'd recommend starting with one first so the PR
can focus on the implementation (unless it is an obvious bug or documentation fix
that will have little conversation).
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Code Refactoring

## How did you test it?
<!--
Did you write an integration/unit/API test to verify the code changes?
Or did you test this change manually (provide relevant screenshots)?
-->
Payment_Method_flows seems working (AE).

## Checklist
<!-- Put an `x` in the boxes that apply -->

- [x] I formatted the code `cargo +nightly fmt --all`
- [x] I addressed lints thrown by `cargo clippy`
- [x] I reviewed the submitted code
- [ ] I added unit tests for my changes where possible


Testing:

Payment_Method_flows seems working (AE).

Patch:
diff --git a/crates/router/src/core/authentication/transformers.rs b/crates/router/src/core/authentication/transformers.rs
index abefd12c77d..d4cad2fbedb 100644
--- a/crates/router/src/core/authentication/transformers.rs
+++ b/crates/router/src/core/authentication/transformers.rs
@@ -168,7 +168,6 @@ pub fn construct_router_data<F: Clone, Req, Res>(
         connector_api_version: None,
         request: request_data,
         response: Err(types::ErrorResponse::default()),
-        payment_method_id: None,
         connector_request_reference_id:
             IRRELEVANT_CONNECTOR_REQUEST_REFERENCE_ID_IN_AUTHENTICATION_FLOW.to_owned(),
         #[cfg(feature = "payouts")]
diff --git a/crates/router/src/core/fraud_check/flows/checkout_flow.rs b/crates/router/src/core/fraud_check/flows/checkout_flow.rs
index f17a1730088..58e82ec21c7 100644
--- a/crates/router/src/core/fraud_check/flows/checkout_flow.rs
+++ b/crates/router/src/core/fraud_check/flows/checkout_flow.rs
@@ -63,7 +63,6 @@ impl ConstructFlowSpecificData<frm_api::Checkout, FraudCheckCheckoutData, FraudC
             connector_auth_type: auth_type,
             description: None,
             return_url: None,
-            payment_method_id: None,
             payment_method_status: None,
             address: self.address.clone(),
             auth_type: storage_enums::AuthenticationType::NoThreeDs,
diff --git a/crates/router/src/core/fraud_check/flows/fulfillment_flow.rs b/crates/router/src/core/fraud_check/flows/fulfillment_flow.rs
index a76408b5d3d..50ebea24878 100644
--- a/crates/router/src/core/fraud_check/flows/fulfillment_flow.rs
+++ b/crates/router/src/core/fraud_check/flows/fulfillment_flow.rs
@@ -71,7 +71,6 @@ pub async fn construct_fulfillment_router_data<'a>(
         connector_auth_type: auth_type,
         description: None,
         return_url: payment_intent.return_url.clone(),
-        payment_method_id: payment_attempt.payment_method_id.clone(),
         address: PaymentAddress::default(),
         auth_type: payment_attempt.authentication_type.unwrap_or_default(),
         connector_meta_data: merchant_connector_account.get_metadata(),
diff --git a/crates/router/src/core/fraud_check/flows/record_return.rs b/crates/router/src/core/fraud_check/flows/record_return.rs
index cba19769d57..ad74f7f7027 100644
--- a/crates/router/src/core/fraud_check/flows/record_return.rs
+++ b/crates/router/src/core/fraud_check/flows/record_return.rs
@@ -62,7 +62,6 @@ impl ConstructFlowSpecificData<RecordReturn, FraudCheckRecordReturnData, FraudCh
             connector_auth_type: auth_type,
             description: None,
             return_url: None,
-            payment_method_id: None,
             address: self.address.clone(),
             auth_type: storage_enums::AuthenticationType::NoThreeDs,
             connector_meta_data: None,
diff --git a/crates/router/src/core/fraud_check/flows/sale_flow.rs b/crates/router/src/core/fraud_check/flows/sale_flow.rs
index c9f5e4dac0a..0ce0c89bd35 100644
--- a/crates/router/src/core/fraud_check/flows/sale_flow.rs
+++ b/crates/router/src/core/fraud_check/flows/sale_flow.rs
@@ -58,7 +58,6 @@ impl ConstructFlowSpecificData<frm_api::Sale, FraudCheckSaleData, FraudCheckResp
             connector_auth_type: auth_type,
             description: None,
             return_url: None,
-            payment_method_id: None,
             address: self.address.clone(),
             auth_type: storage_enums::AuthenticationType::NoThreeDs,
             connector_meta_data: None,
diff --git a/crates/router/src/core/fraud_check/flows/transaction_flow.rs b/crates/router/src/core/fraud_check/flows/transaction_flow.rs
index dc385093f23..5634916b212 100644
--- a/crates/router/src/core/fraud_check/flows/transaction_flow.rs
+++ b/crates/router/src/core/fraud_check/flows/transaction_flow.rs
@@ -69,7 +69,6 @@ impl
             connector_auth_type: auth_type,
             description: None,
             return_url: None,
-            payment_method_id: None,
             address: self.address.clone(),
             auth_type: storage_enums::AuthenticationType::NoThreeDs,
             connector_meta_data: None,
diff --git a/crates/router/src/core/mandate/utils.rs b/crates/router/src/core/mandate/utils.rs
index 7b4933812e5..ec438ee6d78 100644
--- a/crates/router/src/core/mandate/utils.rs
+++ b/crates/router/src/core/mandate/utils.rs
@@ -59,7 +59,6 @@ pub async fn construct_mandate_revoke_router_data(
             connector_mandate_id: mandate.connector_mandate_id,
         },
         response: Err(types::ErrorResponse::get_not_implemented()),
-        payment_method_id: None,
         connector_request_reference_id:
             IRRELEVANT_CONNECTOR_REQUEST_REFERENCE_ID_IN_MANDATE_REVOKE_FLOW.to_string(),
         test_mode: None,
diff --git a/crates/router/src/core/payments/helpers.rs b/crates/router/src/core/payments/helpers.rs
index 6a1a779fd1f..bcc911e497a 100644
--- a/crates/router/src/core/payments/helpers.rs
+++ b/crates/router/src/core/payments/helpers.rs
@@ -3244,7 +3244,6 @@ pub fn router_data_type_conversion<F1, F2, Req1, Req2, Res1, Res2>(
         description: router_data.description,
         payment_id: router_data.payment_id,
         payment_method: router_data.payment_method,
-        payment_method_id: router_data.payment_method_id,
         return_url: router_data.return_url,
         status: router_data.status,
         attempt_id: router_data.attempt_id,
diff --git a/crates/router/src/core/payments/operations/payment_response.rs b/crates/router/src/core/payments/operations/payment_response.rs
index 4580181d394..47d659b5ed2 100644
--- a/crates/router/src/core/payments/operations/payment_response.rs
+++ b/crates/router/src/core/payments/operations/payment_response.rs
@@ -966,7 +966,10 @@ async fn payment_response_update_tracker<F: Clone, T: types::Capturable>(
                             status: updated_attempt_status,
                             connector: None,
                             connector_transaction_id,
-                            payment_method_id: router_data.payment_method_id,
+                            payment_method_id: payment_data
+                                .payment_attempt
+                                .payment_method_id
+                                .clone(),
                             error_code: Some(reason.clone().map(|cd| cd.code)),
                             error_message: Some(reason.clone().map(|cd| cd.message)),
                             error_reason: Some(reason.map(|cd| cd.message)),
diff --git a/crates/router/src/core/payments/retry.rs b/crates/router/src/core/payments/retry.rs
index 71cded04e1a..58c58ffaef8 100644
--- a/crates/router/src/core/payments/retry.rs
+++ b/crates/router/src/core/payments/retry.rs
@@ -384,7 +384,7 @@ where
                         .connector_response_reference_id
                         .clone(),
                     authentication_type: None,
-                    payment_method_id: router_data.payment_method_id,
+                    payment_method_id: payment_data.payment_attempt.payment_method_id.clone(),
                     mandate_id: payment_data
                         .mandate_id
                         .clone()
diff --git a/crates/router/src/core/payments/transformers.rs b/crates/router/src/core/payments/transformers.rs
index eba5768a9ce..b891998dae3 100644
--- a/crates/router/src/core/payments/transformers.rs
+++ b/crates/router/src/core/payments/transformers.rs
@@ -141,7 +141,6 @@ where
         connector_auth_type: auth_type,
         description: payment_data.payment_intent.description.clone(),
         return_url: payment_data.payment_intent.return_url.clone(),
-        payment_method_id: payment_data.payment_attempt.payment_method_id.clone(),
         address: payment_data
             .address
             .unify_with_payment_method_data_billing(payment_method_data_billing),
diff --git a/crates/router/src/core/utils.rs b/crates/router/src/core/utils.rs
index c67aafe938f..c7a22e56897 100644
--- a/crates/router/src/core/utils.rs
+++ b/crates/router/src/core/utils.rs
@@ -160,7 +160,6 @@ pub async fn construct_payout_router_data<'a, F>(
         connector_auth_type,
         description: None,
         return_url: payouts.return_url.to_owned(),
-        payment_method_id: None,
         address,
         auth_type: enums::AuthenticationType::default(),
         connector_meta_data: merchant_connector_account.get_metadata(),
@@ -311,7 +310,6 @@ pub async fn construct_refund_router_data<'a, F>(
         connector_auth_type: auth_type,
         description: None,
         return_url: payment_intent.return_url.clone(),
-        payment_method_id: payment_attempt.payment_method_id.clone(),
         // Does refund need shipping/billing address ?
         address: PaymentAddress::default(),
         auth_type: payment_attempt.authentication_type.unwrap_or_default(),
@@ -557,7 +555,6 @@ pub async fn construct_accept_dispute_router_data<'a>(
         connector_auth_type: auth_type,
         description: None,
         return_url: payment_intent.return_url.clone(),
-        payment_method_id: payment_attempt.payment_method_id.clone(),
         address: PaymentAddress::default(),
         auth_type: payment_attempt.authentication_type.unwrap_or_default(),
         connector_meta_data: merchant_connector_account.get_metadata(),
@@ -652,7 +649,6 @@ pub async fn construct_submit_evidence_router_data<'a>(
         connector_auth_type: auth_type,
         description: None,
         return_url: payment_intent.return_url.clone(),
-        payment_method_id: payment_attempt.payment_method_id.clone(),
         address: PaymentAddress::default(),
         auth_type: payment_attempt.authentication_type.unwrap_or_default(),
         connector_meta_data: merchant_connector_account.get_metadata(),
@@ -745,7 +741,6 @@ pub async fn construct_upload_file_router_data<'a>(
         connector_auth_type: auth_type,
         description: None,
         return_url: payment_intent.return_url.clone(),
-        payment_method_id: payment_attempt.payment_method_id.clone(),
         address: PaymentAddress::default(),
         auth_type: payment_attempt.authentication_type.unwrap_or_default(),
         connector_meta_data: merchant_connector_account.get_metadata(),
@@ -842,7 +837,6 @@ pub async fn construct_defend_dispute_router_data<'a>(
         connector_auth_type: auth_type,
         description: None,
         return_url: payment_intent.return_url.clone(),
-        payment_method_id: payment_attempt.payment_method_id.clone(),
         address: PaymentAddress::default(),
         auth_type: payment_attempt.authentication_type.unwrap_or_default(),
         connector_meta_data: merchant_connector_account.get_metadata(),
@@ -930,7 +924,6 @@ pub async fn construct_retrieve_file_router_data<'a>(
         connector_auth_type: auth_type,
         description: None,
         return_url: None,
-        payment_method_id: None,
         address: PaymentAddress::default(),
         auth_type: diesel_models::enums::AuthenticationType::default(),
         connector_meta_data: merchant_connector_account.get_metadata(),
diff --git a/crates/router/src/core/webhooks/utils.rs b/crates/router/src/core/webhooks/utils.rs
index 739d7b20fdd..3bf8c7c7f21 100644
--- a/crates/router/src/core/webhooks/utils.rs
+++ b/crates/router/src/core/webhooks/utils.rs
@@ -83,7 +83,6 @@ pub async fn construct_webhook_router_data<'a>(
         connector_auth_type: auth_type,
         description: None,
         return_url: None,
-        payment_method_id: None,
         address: PaymentAddress::default(),
         auth_type: diesel_models::enums::AuthenticationType::default(),
         connector_meta_data: None,
diff --git a/crates/router/src/types.rs b/crates/router/src/types.rs
index 639efe3f069..77d53584dab 100644
--- a/crates/router/src/types.rs
+++ b/crates/router/src/types.rs
@@ -303,9 +303,6 @@ pub struct RouterData<Flow, Request, Response> {
     /// Contains flow-specific data that the connector responds with.
     pub response: Result<Response, ErrorResponse>,
 
-    /// Contains any error response that the connector returns.
-    pub payment_method_id: Option<String>,
-
     /// Contains a reference ID that should be sent in the connector request
     pub connector_request_reference_id: String,
 
@@ -1541,7 +1538,6 @@ impl<F1, F2, T1, T2> From<(&RouterData<F1, T1, PaymentsResponseData>, T2)>
             amount_captured: data.amount_captured,
             access_token: data.access_token.clone(),
             response: data.response.clone(),
-            payment_method_id: data.payment_method_id.clone(),
             payment_id: data.payment_id.clone(),
             session_token: data.session_token.clone(),
             reference_id: data.reference_id.clone(),
@@ -1602,7 +1598,6 @@ impl<F1, F2>
             amount_captured: data.amount_captured,
             access_token: data.access_token.clone(),
             response: data.response.clone(),
-            payment_method_id: data.payment_method_id.clone(),
             payment_id: data.payment_id.clone(),
             session_token: data.session_token.clone(),
             reference_id: data.reference_id.clone(),
diff --git a/crates/router/src/types/api/verify_connector.rs b/crates/router/src/types/api/verify_connector.rs
index 55dc4a2bf04..39891a7075d 100644
--- a/crates/router/src/types/api/verify_connector.rs
+++ b/crates/router/src/types/api/verify_connector.rs
@@ -81,7 +81,6 @@ impl VerifyConnectorData {
             payment_method: storage_enums::PaymentMethod::Card,
             amount_captured: None,
             preprocessing_id: None,
-            payment_method_id: None,
             connector_customer: None,
             connector_auth_type: self.connector_auth.clone(),
             connector_meta_data: None,
diff --git a/crates/router/tests/connectors/aci.rs b/crates/router/tests/connectors/aci.rs
index 4da849c4e2a..710d90a4ea3 100644
--- a/crates/router/tests/connectors/aci.rs
+++ b/crates/router/tests/connectors/aci.rs
@@ -33,7 +33,6 @@ fn construct_payment_router_data() -> types::PaymentsAuthorizeRouterData {
         description: Some("This is a test".to_string()),
         return_url: None,
         payment_method_status: None,
-        payment_method_id: None,
         request: types::PaymentsAuthorizeData {
             amount: 1000,
             currency: enums::Currency::USD,
@@ -133,7 +132,6 @@ fn construct_refund_router_data<F>() -> types::RefundsRouterData<F> {
         connector: "aci".to_string(),
         payment_id: uuid::Uuid::new_v4().to_string(),
         attempt_id: uuid::Uuid::new_v4().to_string(),
-        payment_method_id: None,
         payment_method_status: None,
         status: enums::AttemptStatus::default(),
         payment_method: enums::PaymentMethod::Card,
diff --git a/crates/router/tests/connectors/utils.rs b/crates/router/tests/connectors/utils.rs
index fd472aa9411..9678eca73f3 100644
--- a/crates/router/tests/connectors/utils.rs
+++ b/crates/router/tests/connectors/utils.rs
@@ -503,7 +503,6 @@ pub trait ConnectorActions: Connector {
             payment_id: uuid::Uuid::new_v4().to_string(),
             attempt_id: uuid::Uuid::new_v4().to_string(),
             status: enums::AttemptStatus::default(),
-            payment_method_id: None,
             auth_type: info
                 .clone()
                 .map_or(enums::AuthenticationType::NoThreeDs, |a| {