Set correct DPR on wayland cursors received from remote buffers
Summary:
It will then be renderered appropriately when painting to the output
buffer.
Test Plan: Updated unit test, plus used with other relevant patches
Reviewers: KWin, graesslin
Reviewed By: KWin, graesslin
Subscribers: kwin
Tags: KWin
Differential Revision: https://phabricator.kde.org/D13606