Issue:
Bug: [FEATURE]: [Stax] Use `connector_response_reference_id` as reference to merchant



### :memo: Feature Description

- Reference id are used to map transactions in the connector’s dashboard.
- Hyperswitch manages several reference ids, such as `payment_id`, `attempt_id`, and `connector_transaction_id` for a single transaction. 
- However, merchants may encounter uncertainty when determining which ID to utilize in the connector dashboard to identify the payment.

### :hammer: Possible Implementation

- When we receive a response from the connector for the payment, we deserialize it and populate the `response` field in RouterData. 
- For the `TransactionResponse` type, we must fill the `connector_response_reference_id` with a corresponding reference id for the merchant to identify the transaction. 
- One might need to have exposure to api docs of the connector for which it is being implemented to decide what to fill in connector_response_reference_id.
- You can check this PR for further reference https://github.com/juspay/hyperswitch/pull/1735

🔖 Note: All the changes needed should be contained within `hyperswitch/crates/router/src/connector/`


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

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

### :package: Have you read the Contributing Guidelines?

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

###  :sparkles: Are you willing to submit a PR?


Pull request description:
## Type of Change
<!-- Put an `x` in the boxes that apply -->

- [ ] Bugfix
- [x] New feature
- [ ] Enhancement
- [ ] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description
<!-- Describe your changes in detail -->
This pull request fixes #2348 issue in STAX and uses connector_response_reference_id as reference to merchant.

### 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
<!--
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).
-->
Fixes #2348 and fixes #2317.

## 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)?
-->


## 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
- [ ] I added a [CHANGELOG](/CHANGELOG.md) entry if applicable


Testing:

Patch:
diff --git a/crates/router/src/connector/stax/transformers.rs b/crates/router/src/connector/stax/transformers.rs
index 42c7c02a363..4ee28be1937 100644
--- a/crates/router/src/connector/stax/transformers.rs
+++ b/crates/router/src/connector/stax/transformers.rs
@@ -23,6 +23,7 @@ pub struct StaxPaymentsRequest {
     is_refundable: bool,
     pre_auth: bool,
     meta: StaxPaymentsRequestMetaData,
+    idempotency_id: Option<String>,
 }
 
 impl TryFrom<&types::PaymentsAuthorizeRouterData> for StaxPaymentsRequest {
@@ -51,6 +52,7 @@ impl TryFrom<&types::PaymentsAuthorizeRouterData> for StaxPaymentsRequest {
                             Err(errors::ConnectorError::InvalidWalletToken)?
                         }
                     }),
+                    idempotency_id: Some(item.connector_request_reference_id.clone()),
                 })
             }
             api::PaymentMethodData::BankDebit(
@@ -69,6 +71,7 @@ impl TryFrom<&types::PaymentsAuthorizeRouterData> for StaxPaymentsRequest {
                             Err(errors::ConnectorError::InvalidWalletToken)?
                         }
                     }),
+                    idempotency_id: Some(item.connector_request_reference_id.clone()),
                 })
             }
             api::PaymentMethodData::BankDebit(_)
@@ -282,6 +285,7 @@ pub struct StaxPaymentsResponse {
     child_captures: Vec<StaxChildCapture>,
     #[serde(rename = "type")]
     payment_response_type: StaxPaymentResponseTypes,
+    idempotency_id: Option<String>,
 }
 
 #[derive(Debug, Deserialize, Serialize)]
@@ -323,12 +327,14 @@ impl<F, T>
         Ok(Self {
             status,
             response: Ok(types::PaymentsResponseData::TransactionResponse {
-                resource_id: types::ResponseId::ConnectorTransactionId(item.response.id),
+                resource_id: types::ResponseId::ConnectorTransactionId(item.response.id.clone()),
                 redirection_data: None,
                 mandate_reference: None,
                 connector_metadata,
                 network_txn_id: None,
-                connector_response_reference_id: None,
+                connector_response_reference_id: Some(
+                    item.response.idempotency_id.unwrap_or(item.response.id),
+                ),
             }),
             ..item.data
         })