Issue:
Bug: [FEATURE]: [PayU] 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
- [x] New feature
- [ ] Enhancement
- [ ] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

## Description
Add connector_request_reference_id support for PayU

- Used `extOrderId` as the reference id based on the [PayU documentation](https://developers.payu.com/europe/api/#tag/Order/operation/create-an-order) reference:

![image](https://github.com/user-attachments/assets/f730028d-1fa4-4222-b2ad-7e2b4caeed9e)


Resolves #2313 


### 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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1. `config`
2. `crates/router/src/configs`
3. `loadtest/config`
-->


## Motivation and Context
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## How did you test it?
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## Checklist
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- [x] I formatted the code `cargo +nightly fmt --all`
- [x] I addressed lints thrown by `cargo clippy`
- [ ] I reviewed the submitted code
- [ ] I added unit tests for my changes where possible


Testing:

Patch:
diff --git a/crates/hyperswitch_connectors/src/connectors/payu/transformers.rs b/crates/hyperswitch_connectors/src/connectors/payu/transformers.rs
index 7b3792c0e24..dc65d6e1d76 100644
--- a/crates/hyperswitch_connectors/src/connectors/payu/transformers.rs
+++ b/crates/hyperswitch_connectors/src/connectors/payu/transformers.rs
@@ -34,6 +34,7 @@ pub struct PayuPaymentsRequest {
     description: String,
     pay_methods: PayuPaymentMethod,
     continue_url: Option<String>,
+    ext_order_id: Option<String>,
 }
 
 #[derive(Debug, Eq, PartialEq, Serialize)]
@@ -133,6 +134,7 @@ impl TryFrom<&types::PaymentsAuthorizeRouterData> for PayuPaymentsRequest {
                     .to_string(),
             ),
             merchant_pos_id: auth_type.merchant_pos_id,
+            ext_order_id: Some(item.connector_request_reference_id.clone()),
             total_amount: item.request.amount,
             currency_code: item.request.currency,
             description: item.description.clone().ok_or(