gdk/wayland: Return pad devices querying for all devices

gdk/wayland: Return pad devices querying for all devices

These devices unfortunately didn't ever get a capability flag in
3.24 (fixed in GTK4). We are very far off into maintenance grounds that
it is not ideal to add new flag values, but we could however return
these devices if GDK_SEAT_CAPABILITY_ALL is being asked.

Do that, so it is possible to deal with pad devices, even if it's
not possible to query them specifically.

Forwarded: https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/6049
Origin: 3.24.39, commit:a9d7198d63d14e049c399914f11ddd37fc034f3a

Gbp-Pq: Name gdk-wayland-Return-pad-devices-querying-for-all-devices.patch