Issue:
Bug: [REFACTOR] : [NMI] Error Message For Connector Implementation



### :memo: Feature Description

- In terms of errors, we are currently throwing a 'not supported' message, which shouldn't be the case as we are yet to decide on the implementation.


### :hammer: Possible Implementation

- In order to manage payment methods that are not implemented by Hyperswitch or yet to be implemented, the connector transformers file should make use of the NotImplemented ConnectorError enum variant.
- By doing so, we will throw same error message for all the Connector Implementation 
- You can check this PR for further reference https://github.com/juspay/hyperswitch/pull/2831


:bookmark: 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
- [ ] New feature
- [ ] Enhancement
- [x] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description
<!-- Describe your changes in detail -->


### Additional Changes

- [ ] This PR modifies the API contract
- [ ] This PR modifies the database schema
- [ ] This PR modifies application configuration/environment variables

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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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## How did you test it?
Make any payment for NMI for any PM which is not implemented, and see for the error message - it should be payment method not implemented
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Did you write an integration/unit/API test to verify the code changes?
Or did you test this change manually (provide relevant screenshots)?
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## 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

resolve #2843 

Testing:
Make any payment for NMI for any PM which is not implemented, and see for the error message - it should be payment method not implemented


Patch:
diff --git a/crates/router/src/connector/nmi/transformers.rs b/crates/router/src/connector/nmi/transformers.rs
index fcf35bfbe37..5b486aae600 100644
--- a/crates/router/src/connector/nmi/transformers.rs
+++ b/crates/router/src/connector/nmi/transformers.rs
@@ -494,10 +494,9 @@ impl TryFrom<&api_models::payments::PaymentMethodData> for PaymentMethod {
                 | api_models::payments::WalletData::WeChatPayQr(_)
                 | api_models::payments::WalletData::CashappQr(_)
                 | api_models::payments::WalletData::SwishQr(_) => {
-                    Err(errors::ConnectorError::NotSupported {
-                        message: utils::SELECTED_PAYMENT_METHOD.to_string(),
-                        connector: "nmi",
-                    })
+                    Err(errors::ConnectorError::NotImplemented(
+                        utils::get_unimplemented_payment_method_error_message("nmi"),
+                    ))
                     .into_report()
                 }
             },
@@ -512,10 +511,9 @@ impl TryFrom<&api_models::payments::PaymentMethodData> for PaymentMethod {
             | api::PaymentMethodData::Upi(_)
             | api::PaymentMethodData::Voucher(_)
             | api::PaymentMethodData::GiftCard(_)
-            | api::PaymentMethodData::CardToken(_) => Err(errors::ConnectorError::NotSupported {
-                message: utils::SELECTED_PAYMENT_METHOD.to_string(),
-                connector: "nmi",
-            })
+            | api::PaymentMethodData::CardToken(_) => Err(errors::ConnectorError::NotImplemented(
+                utils::get_unimplemented_payment_method_error_message("nmi"),
+            ))
             .into_report(),
         }
     }