EventDataStreamFactory - add row_file_sink method
This will make it easier to write integration tests that ensure we are able to pass the output of our pipelines through to the eventutilities-flink JsonRowSerializationSchema serializer. It will be easier to write these tests by sinking datastreams to files, and then ensuring that those files have the correct content.
This will depend on a wikimedia-event-utilities release 1.2.4.
Bug: T326565 Bug: T326536 Depends-On: https://gerrit.wikimedia.org/r/c/wikimedia-event-utilities/+/888250