Feature request: Include X-Ray trace ID in default JSON API Gateway access log format

https://github.com/aws/aws-cdk/blob/6c1eda9dd5fa46feddb33c96262d06a21818c898/packages/aws-cdk-lib/aws-apigateway/lib/access-log.ts#L748-L772

The current implementation of `apigateway.AccessLogFormat.jsonWithStandardFields()` does not include the `$context.xrayTraceId` field, which is very useful when X-Ray is enabled. I suggest adding it to the default implementation or including it as an optional field.

Start in packages/aws-cdk-lib/aws-apigateway/lib/access-log.ts at the jsonWithStandardFields() implementation around lines 748-772. Review how the default JSON access-log format is assembled and confirm the expected behavior for the proposed X-Ray trace ID field. Done means the default format includes $context.xrayTraceId, or the issue's optional-field alternative is implemented and verified.

Written by the indexing model from the issue text.