Bug: Update open-api spec of /relay request to make the data untagged enum



Update open-api spec of /relay request to make the data untagged enum
diff --git a/crates/openapi/src/routes/relay.rs b/crates/openapi/src/routes/relay.rs
index 9100bf47f75..180fed66492 100644
--- a/crates/openapi/src/routes/relay.rs
+++ b/crates/openapi/src/routes/relay.rs
@@ -13,8 +13,10 @@
                     "connector_id": "mca_5apGeP94tMts6rg3U3kR",
                     "type": "refund",
                     "data": {
-                        "amount": 6540,
-                        "currency": "USD"
+                        "refund": {
+                            "amount": 6540,
+                            "currency": "USD"
+                        }
                     }
                 })
             )

## Type of Change
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- [ ] Bugfix
- [ ] New feature
- [ ] Enhancement
- [ ] Refactoring
- [ ] Dependency updates
- [x] Documentation
- [ ] CI/CD

## Description
<!-- Describe your changes in detail -->
Update open-api spec of /relay request to make the data untagged enum.

### 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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## 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`
- [x] I reviewed the submitted code
- [ ] I added unit tests for my changes where possible
