Multiple UI fixes

Fixes multiple UI issues

changed milestone to %3.5.x

added UI UX bug labels

requested review from @Skantes

For the first commit, the wrong issue is linked, it should close #2520 (closed) and not #2523

Apart from that LGTM

added 32 commits

• 00759b1c...38663c5a - 29 commits from branch videolan:master
• 25d2ac49 - Trigger a dialog for history deletion
• 3e7b9700 - Fix add to group dialog empty state and text
• bb35524b - Empty view: add an "empty search" state

Compare with previous version

enabled an automatic merge when the pipeline for bb35524b succeeds

merged

mentioned in issue #2523