Finalize bulk_import_failures backfill migrations

What does this MR do and why?

This migration was finished, you can confirm the status using our batched background migration chatops commands.

To confirm it is finished you can run:

/chatops run batched_background_migrations status 2000829

The last time this background migration was triggered was in:

• https://gitlab.com/gitlab-org/gitlab/blob/789f0f980e19aeb99c88a5187d91d86e0114c0b6/db/post_migrate/20250205194756_queue_backfill_bulk_import_failures_namespace_id.rb

You can read more about the process for finalizing batched background migrations in https://docs.gitlab.com/ee/development/database/batched_background_migrations.html.

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Before	After

How to set up and validate locally

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.