Disable unused tags count cache for Projects, Builds and Runners

What does this MR do?

Disables unused tags count cache for Projects, Builds and Runners

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

• I haven't found anywhere where the count per tag was used.
• I wondered about whether we should explicitly remove the tag cache table or not. Or at least 0 all values.

Why was this MR needed?

The cache caused DB UPDATE's whenev a tag was added or removed. Which in case of bulk project removal caused unintended flood of UPDATES for every tag such project had.

Does this MR meet the acceptance criteria?

• Changelog entry added
• Tests
  • All builds are passing
• 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 #27989 (closed)