When a transition is created for the allocation change, it will delay
the new allocation box getting set depending on transition details.
This, however, means that e.g. the 'needs_allocation' flag never gets
cleared if a transition is created, causing other parts of the code to
get confused thinking it didn't pass through a layout step before paint.
Fix this by calling clutter_actor_allocate_internal() with the current
allocation box if a transition was created, so that we'll properly clear
'needs_allocation' flag.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1345
da633dcc52