[x11] Apply "Block compositing" rule right away
Summary:
When the user changes "Block compositing" rule, apply it immediately.
BUG: 415903
Reviewers: KWin, davidedmundson
Reviewed By: KWin, davidedmundson
Subscribers: kwin
Tags: KWin
Differential Revision: https://phabricator.kde.org/D26708