backend/wayland: Fix computing output pixel size in xdg_toplevel.configure handler
Currently, we pass the logical size but setGeometry() expects the size in device pixels. It fixes "kwin_wayland --scale 2" shrinking on every configure event.
Currently, we pass the logical size but setGeometry() expects the size in device pixels. It fixes "kwin_wayland --scale 2" shrinking on every configure event.