WaylandWindow: Update client output already in the constructor
It was only updated when the client moved/resized or the outputs themselves changed.
Noticed my lockscreen wallpaper had the wrong scale for a frame or so when waking up from suspend. This is no longer the case with this.
Also the audio indicator in my task manager is no longer pixelated (though I don’t understand why it didn’t update when the DPR change eventually arrived).