Issue:
Bug: [BUG] CUSTOMERREQUEST refund reason not supported in Adyen



### Bug Description

CUSTOMERREQUEST refund reason not supported in Adyen

### Expected Behavior

CUSTOMERREQUEST refund reason should be supported in Adyen.

### Actual Behavior

CUSTOMERREQUEST refund reason not supported in Adyen

### Steps To Reproduce

Provide an unambiguous set of steps to reproduce this bug. Include code or configuration to reproduce, if relevant.
1. Go to '...'
2. Click on '....'
3. Scroll down to '....'


### Context For The Bug

_No response_

### Environment

Are you using hyperswitch hosted version? Yes/No
If yes, please provide the value of the `x-request-id` response header to help us debug your issue.

If not (or if building/running locally), please provide the following details:
1. Operating System or Linux distribution:
2. Rust version (output of `rustc --version`): ``
3. App version (output of `cargo r --features vergen -- --version`): ``


### Have you spent some time checking if this bug 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 -->

- [x] Bugfix
- [ ] New feature
- [ ] Enhancement
- [ ] Refactoring
- [ ] Dependency updates
- [ ] Documentation
- [ ] CI/CD

Closes this [issue](https://github.com/juspay/hyperswitch/issues/9034)

## Description
<!-- Describe your changes in detail -->

Added Support for CUSTOMERREQUEST Refund Reason in Adyen

### 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).
-->


## 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)?
-->

Postman Test:

Refunds:

Request:

```
curl --location 'http://localhost:8080/refunds' \
--header 'Content-Type: application/json' \
--header 'Accept: application/json' \
--header 'api-key: dev_KYKqKi3f1IgAl2wzfLwajdyMApB5XvTmX7SjYWpAcuLRnYxXToxXjDDuMoKPJ5h2' \
--data '{
    "payment_id": "pay_rcvdW42PBSd2ik1tYEpA",
    "amount": 1000,
    "reason": "CustomerRequest",
    "refund_type": "instant",
    "metadata": {
        "udf1": "value1",
        "new_customer": "true",
        "login_date": "2019-09-10T10:11:12Z"
    } 
}'
```

Response:

```
{
    "refund_id": "ref_3UOUCY4WziTz0iWhRGjT",
    "payment_id": "pay_rcvdW42PBSd2ik1tYEpA",
    "amount": 1000,
    "currency": "USD",
    "status": "pending",
    "reason": "CUSTOMER REQUEST",
    "metadata": {
        "udf1": "value1",
        "new_customer": "true",
        "login_date": "2019-09-10T10:11:12Z"
    },
    "error_message": null,
    "error_code": null,
    "unified_code": null,
    "unified_message": null,
    "created_at": "2025-08-06T04:02:37.782Z",
    "updated_at": "2025-08-06T04:02:39.280Z",
    "connector": "adyen",
    "profile_id": "pro_H4NAjXx3vY9NI4nQbXom",
    "merchant_connector_id": "mca_EC2PLdAi5hhl8zAKbt0G",
    "split_refunds": null,
    "issuer_error_code": null,
    "issuer_error_message": null
}
```


## 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:


Postman Test:

Refunds:

Request:

```
curl --location 'http://localhost:8080/refunds' \
--header 'Content-Type: application/json' \
--header 'Accept: application/json' \
--header 'api-key: dev_KYKqKi3f1IgAl2wzfLwajdyMApB5XvTmX7SjYWpAcuLRnYxXToxXjDDuMoKPJ5h2' \
--data '{
    "payment_id": "pay_rcvdW42PBSd2ik1tYEpA",
    "amount": 1000,
    "reason": "CustomerRequest",
    "refund_type": "instant",
    "metadata": {
        "udf1": "value1",
        "new_customer": "true",
        "login_date": "2019-09-10T10:11:12Z"
    } 
}'
```

Response:

```
{
    "refund_id": "ref_3UOUCY4WziTz0iWhRGjT",
    "payment_id": "pay_rcvdW42PBSd2ik1tYEpA",
    "amount": 1000,
    "currency": "USD",
    "status": "pending",
    "reason": "CUSTOMER REQUEST",
    "metadata": {
        "udf1": "value1",
        "new_customer": "true",
        "login_date": "2019-09-10T10:11:12Z"
    },
    "error_message": null,
    "error_code": null,
    "unified_code": null,
    "unified_message": null,
    "created_at": "2025-08-06T04:02:37.782Z",
    "updated_at": "2025-08-06T04:02:39.280Z",
    "connector": "adyen",
    "profile_id": "pro_H4NAjXx3vY9NI4nQbXom",
    "merchant_connector_id": "mca_EC2PLdAi5hhl8zAKbt0G",
    "split_refunds": null,
    "issuer_error_code": null,
    "issuer_error_message": null
}
```

Patch:
diff --git a/crates/hyperswitch_connectors/src/connectors/adyen/transformers.rs b/crates/hyperswitch_connectors/src/connectors/adyen/transformers.rs
index 63c1b0d8a32..f30732173a7 100644
--- a/crates/hyperswitch_connectors/src/connectors/adyen/transformers.rs
+++ b/crates/hyperswitch_connectors/src/connectors/adyen/transformers.rs
@@ -1415,7 +1415,7 @@ impl FromStr for AdyenRefundRequestReason {
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         match s.to_uppercase().as_str() {
             "FRAUD" => Ok(Self::FRAUD),
-            "CUSTOMER REQUEST" => Ok(Self::CUSTOMERREQUEST),
+            "CUSTOMER REQUEST" | "CUSTOMERREQUEST" => Ok(Self::CUSTOMERREQUEST),
             "RETURN" => Ok(Self::RETURN),
             "DUPLICATE" => Ok(Self::DUPLICATE),
             "OTHER" => Ok(Self::OTHER),