docs: Add samples and test for ingestion from Kafka sources

[michaelpri10]

Adds tests and samples for ingestion from Kafka sources

[snippet-bot]

Here is the summary of changes.

You are about to add 3 region tags.

• samples/snippets/publisher.py:197, tag pubsub_create_topic_with_aws_msk_ingestion
• samples/snippets/publisher.py:243, tag pubsub_create_topic_with_azure_event_hubs_ingestion
• samples/snippets/publisher.py:293, tag pubsub_create_topic_with_confluent_cloud_ingestion

---

This comment is generated by snippet-bot.
If you find problems with this result, please file an issue at:
https://github.com/googleapis/repo-automation-bots/issues.
To update this comment, add snippet-bot:force-run label or use the checkbox below:

• Refresh this comment

[mukund-ananthu]

@michaelpri10 Please fix failing presubmit tests

[michaelpri10]

@michaelpri10 Please fix failing presubmit tests

@mukund-ananthu Some tests still running, but I've fixed the failing tests.

[mukund-ananthu]

Enabled automerge and LGTM'd PR. PR merging now dependent on pending presubmit check completion.

cc: @michaelpri10 @beltran