feat(PubSub): Add create_topic_with_confluent_cloud_ingestion sample

[cy-yun]

https://buganizer.corp.google.com/issues/390688171

[snippet-bot]

Here is the summary of changes.

You are about to add 1 region tag.

• pubsub/api/src/create_topic_with_confluent_cloud_ingestion.php:27, 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