With 734a185915464d2da32b6b1251c8af9a631b0f8c an optimization was
introduced to only pick on events which can actually cause the pointer
to move. In case of touch events, the first event (TOUCH_BEGIN) will
already move the touchpoint though, and we'll send our crossing
CLUTTER_ENTER event to the actor this TOUCH_BEGIN happened on.
So fix this embarrassing bug that caused touch input to break by also
picking to find an event-actor on TOUCH_BEGIN events.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1733>
1922896f07