Backfill projects organization_id

What does this MR do and why?

Backfill projects' organization_id column to the default organization (id=1).

This is a no-op on our current prod data but it is needed to guarantee records in others instances (self-managed) are correctly populated.

Query Plans

Note: The parameters are mocked since there's no record that matches organization_id IS NULL in practice.

• First Batch
  • Select Start: https://console.postgres.ai/gitlab/gitlab-production-main/sessions/33230/commands/102599
  • Select End: https://console.postgres.ai/gitlab/gitlab-production-main/sessions/33230/commands/102602
  • Update: https://console.postgres.ai/gitlab/gitlab-production-main/sessions/33230/commands/102603
• Second Batch
  • Select End: https://console.postgres.ai/gitlab/gitlab-production-main/sessions/33230/commands/102604
  • Update: https://console.postgres.ai/gitlab/gitlab-production-main/sessions/33230/commands/102605
• Non-batched: https://console.postgres.ai/gitlab/gitlab-production-main/sessions/32698/commands/100836

MR acceptance checklist

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

Screenshots or screen recordings

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How to set up and validate locally

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Closes #502507 (closed) Related to #499665 (closed)