Summary:
If user selects a shortcut to trigger the effect, that shortcut won't
work after the KCM is closed because we don't save it.
BUG: 400351
FIXED-IN: 5.14.3
Test Plan:
* Specified custom shortcut to trigger the effect;
* Closed the KCM;
* Pressed the shortcut, a thumbnail appeared.
Reviewers: #kwin, graesslin
Reviewed By: #kwin, graesslin
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D16456
00c9b4c1c9