Summary:
Returning a reference to a value on the stack is broken.
This caused kwin_wayland to crash in openQA with a nullptr deref.
BUG: 407199
Test Plan: Only build tested.
Reviewers: #kwin, zzag
Reviewed By: #kwin, zzag
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D21085