wayland: Correctly compare refresh rates when applying config
KScreen refresh rate is in Hz, the wayland protocol uses mHz. In order to address the issue, this change makes the WaylandOutputDeviceMode provide the refresh rate in the same unit as KScreen::Mode, i.e. Hz.
Co-authored-by: Vlad Zahorodnii vlad.zahorodnii@kde.org (cherry picked from commit 87c90727)