fix: skip mtime hack for tag search

[kesselb]

Summary

TODO

• CI

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[miaulalala]

/backport to stable27

[icewind1991]

I'm still not convinced that this will lead to better performance in most cases, having mysql use the index for the mtime ORDER (seems to) stop it from using any index for the WHERE clauses.

And while there are certainly cases where this is fine, I believe that in more cases the query gains more performance from being able to use the the index for filtering the storages to search in.