wayland/toplevel: Don't alwyas skip changing xdg_toplevel state

wayland/toplevel: Don't alwyas skip changing xdg_toplevel state

We only called xdg_toplevel.(un)set_maximize() if the toplevel layout
changed, but this misses the case when the compositor had changed the
maximized state. Change it to call the xdg_toplevel request if either
the local layout changed, or if the layout differs from the current
state.

This fixes an issue where one couldn't unmaximize a window by double
clicking the titlebar that, had previously been maximized e.g. using a
keyboard binding.

Do the same for fullscreen.