docs: Add workflows to support polling for BigQuery job completion

[camiekim]

Fixes b/505474210

cl/906554929

• [x ] Tests pass
• [ n/a] Appropriate changes to README are included in PR

[snippet-bot]

Here is the summary of changes.

You are about to add 2 region tags.

• src/poll_bigquery_job_auto.workflows.yaml:15, tag workflows_auto_bq_poll
• src/poll_bigquery_job_manual.workflows.yaml:15, tag workflows_manual_bq_poll

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