Fix group labels page timeout if many projects and labels

What does this MR do?

Attempt to fix https://gitlab.com/gitlab-org/gitlab-ce/issues/51221 as I can't reproduce it locally. Basically its revert of this line change.

Why?

LabelsFinder has too much complexity. We build crazy queries to be able to have one class to solve all possible label searches. I believe it is a wrong approach. I think the right way to proceed in the future is to have few small finders without many conditions inside. Each finder should serve one purpose and optimized to a specific page/params

What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ce/issues/51221

Does this MR meet the acceptance criteria?

• [-] Changelog entry added, if necessary
• [-] Documentation created/updated
• [-] Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• [-] Conforms to the database guides