Issue:
Bug: [FEATURE]: [Klarna] Use `connector_request_reference_id` as reference to the connector



### :memo: Feature Description 

- We transmit our reference id from Hyperswitch to the connector, enabling merchants to subsequently locate the payment within the connector dashboard.
- Presently, there is a lack of uniformity in this process, as some implementations employ `payment_id` while others utilize `attempt_id`.
- This inconsistency arises from the fact that `payment_id` and `attempt_id` correspond to two distinct entities within our system.

### :hammer: Possible Implementation 

- To mitigate this confusion, we've introduced a new field called `connector_request_reference_id` in our RouterData. 
- This id should replace them as a reference id to the connector for payment request. 
- One might need to have exposure to api docs of the connector for which it is being implemented.
- You can check this PR for further reference https://github.com/juspay/hyperswitch/pull/2052

: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
- [x] Enhancement
- [x] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description
<!-- Describe your changes in detail -->
Included a `merchant_reference1` field in `KlarnaPaymentsRequest` and map it to `connector_request_reference_id` 


### 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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## How did you test it?
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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


Testing:

Patch:
diff --git a/crates/router/src/connector/klarna/transformers.rs b/crates/router/src/connector/klarna/transformers.rs
index b31d56d51b9..31e356d4765 100644
--- a/crates/router/src/connector/klarna/transformers.rs
+++ b/crates/router/src/connector/klarna/transformers.rs
@@ -45,6 +45,7 @@ pub struct KlarnaPaymentsRequest {
     order_amount: i64,
     purchase_country: String,
     purchase_currency: enums::Currency,
+    merchant_reference1: String,
 }
 
 #[derive(Default, Debug, Deserialize)]
@@ -140,6 +141,7 @@ impl TryFrom<&KlarnaRouterData<&types::PaymentsAuthorizeRouterData>> for KlarnaP
                         total_amount: i64::from(data.quantity) * (data.amount),
                     })
                     .collect(),
+                merchant_reference1: item.router_data.connector_request_reference_id.clone(),
             }),
             None => Err(report!(errors::ConnectorError::MissingRequiredField {
                 field_name: "product_name"