Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3157>
This is ATM unused, but will be used to trigger cancellation of any active gesture. Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2640>
Update the pointer gestures protocol to version 3 and implement the new hold gesture. Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1830>