docs(pubsub): Fix region tags for Pub/Sub ingestion from GCS samples

[michaelpri10]

Uses the correct START and END tags to specify the ingestion from GCS samples. This will allow DevRel automation to find this snippet.

---

This change is 

[dbolduc]

/gcbrun

[snippet-bot]

Here is the summary of changes.

You are about to add 1 region tag.

• google/cloud/pubsub/samples/topic_admin_samples.cc:218, tag pubsub_create_topic_with_cloud_storage_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

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.26%. Comparing base (2e14032) to head (221f313).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #14773      +/-   ##
==========================================
- Coverage   93.27%   93.26%   -0.01%     
==========================================
  Files        2314     2314              
  Lines      208092   208092              
==========================================
- Hits       194100   194083      -17     
- Misses      13992    14009      +17     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.