[yaml]: uncomment WriteToKafka portion of test

[derrickaw]

Tried uncommenting the entire Kafka test to see if it ran with self hosted runner, but still hits that timeout input queue.
So just uncommenting out the WriteToKafka portion.

https://github.com/apache/beam/issues/35272

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[derrickaw]

failure not related

[derrickaw]

assign set of reviewers

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