Fix project records with invalid visibility_level values

What does this MR do?

Introduce a migration to fix up some invalid rows in the database, caused by the AddVisibilityLevelToGroups migration.

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

Is a single UPDATE politic or should I move this to a post-update migration and run one update per bad project?

Why was this MR needed?

Bad data existing in the wild

Does this MR meet the acceptance criteria?

• Changelog entry added
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #22699 (closed)