[3.32] display: Dispose Stack after Compositor and X11
As per commit 7718e67f, destroying the compositor causes destroying window actors and this leads to stack changes, but at this point the stack was already disposed and cleared.
So, clear the stack when any component that could use it (compositor, and X11) has already been destroyed. As consequence, also the stamps should be destroyed at later point.
(cherry-picked from commit e94a0fce)