Backfill p_ci_builds bigint conversion columns

What does this MR do and why?

This is the step to backfill bigint conversion columns for:

• p_ci_builds.auto_canceled_by_id
• p_ci_builds.commit_id
• p_ci_builds.erased_by_id
• p_ci_builds.project_id
• p_ci_builds.runner_id
• p_ci_builds.trigger_request_id
• p_ci_builds.upstream_pipeline_id
• p_ci_builds.user_id

See https://docs.gitlab.com/ee/development/database/avoiding_downtime_in_migrations.html#initialize-the-conversion-and-start-migrating-existing-data-release-n

• The bigint conversion is initialized at !129332 (merged) and !135590 (merged)

Screenshots or screen recordings

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Before	After

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #422834 (closed)