Resolve "Skip repository-changing events on Geo secondaries if the repository hasn't been backfilled yet"

What does this MR do?

Skip repository-changing events on Geo secondaries if the repository hasn't been backfilled yet.

Are there points in the code the reviewer needs to double check?

Are there other events that we should skip?

Why was this MR needed?

If a legacy-storage project that hasn't yet been backfilled on the secondary is renamed, we try (and fail) to move the project and wiki repositories. However, we know this will fail and is unnecessary.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• Internationalization required/considered
• If paid feature, have we considered GitLab.com plan and how it works for groups and is there a design for promoting it to users who aren't on the correct plan
• End-to-end tests pass (package-qa manual pipeline job)

What are the relevant issue numbers?

Closes #4870 (closed)