Dashboard: Make dashboard search faster

[knuzhdin]

What is this feature?

This fix significantly reduces dashboard search time for large installations (tested with MySQL backend). Since all filters are collapsed by AND operator, the order does not matter for the result output, but greatly impacts the speed of the operation.

Why do we need this feature?

Suggestions and searches for dashboards especially for non-admin users become about x100 times faster. This is not so noticable for small installations. But for installations with ~50k dashboards, ~20k users and ~200k permissions is reduces search time from 5min to 0.3sec

Who is this feature for?

Everyone, who is searching dashboards by name on large installations (possibly only with MySQL backend)

Which issue(s) does this PR fix?:

Fixes #69659

Special notes for your reviewer:

Please check that:

• It works as expected from a user's perspective.
• If this is a pre-GA feature, it is behind a feature toggle.
• The docs are updated, and if this is a notable improvement, it's added to our What's New doc.

[knuzhdin]

Same PR, bad author - #77161 - discussion here

Please check this PR @mckn @DanCech @zserge @RichiH

[DanCech]

Merged! Thanks for all your efforts to get this over the line 🥇