Improve projects indexes

What does this MR do?

This MR implements suggestion https://gitlab.com/gitlab-com/infrastructure/issues/4525#note_86023801

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

Why was this MR needed?

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Conform by the code review guidelines
  • Has been reviewed by a Backend maintainer
  • Has been reviewed by a Database specialist
• Conform by the merge request performance guides
• Conform by the style guides
• Conform by the database guides
• If you have multiple commits, please combine them into a few logically organized commits by squashing them
• End-to-end tests pass (package-and-qa manual pipeline job)

What are the relevant issue numbers?

https://gitlab.com/gitlab-com/infrastructure/issues/4525