oad runtime exception caused by retry-after header with integer value

The [Breaking Change (Cross-Version) check in PR 21841](https://github.com/Azure/azure-rest-api-specs/pull/21841/checks?check_run_id=11184536197) fails with an oad runtime exception:


Through local experimentation I found that the runtime exception is caused by examples that contain a `retry-after` header in the response with an integer value.

The `retry-after` header is defined in the REST API as `type: integer, format: int32` so it makes sense to specify it in the example as an integer value.

Start by reproducing the Breaking Change (Cross-Version) check from PR 21841 with an example response containing an integer retry-after header. Trace the runtime exception in the openapi-diff tool and verify that the check completes successfully while preserving the integer header value.

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