[Improvement]: Add Filter by relation support in search modal dialog

[prunepal3339]

Improvement description

Filter by relation feature is available in normal folder grids while it's not there in case of search modals.
Search Modal:

Folder Grid:

Story: Make filter by relation feature available in Search Modal

[github-actions]

Thanks a lot for reporting the issue. We did not consider the issue as "Pimcore:Priority", "Pimcore:ToDo" or "Pimcore:Backlog", so we're not going to work on that anytime soon. Please create a pull request to fix the issue if this is a bug report. We'll then review it as quickly as possible. If you're interested in contributing a feature, please contact us first here before creating a pull request. We'll then decide whether we'd accept it or not. Thanks for your understanding.