community/gnome-shell: Add patch to fix crash on startup when OSK is enabled

See https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/7912.

Patch taken from https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3476.

(Spotted this on my main PC which had the OSK enabled in GDM due to prior keyboardless shenanigans, I don't doubt (though I haven't tested) that this could affect e.g. postmarketOS devices using the OSK as well. (EDIT: I tested on a pmOS device and it seems that this only happens if OSK is manually enabled in accessibility settings, not when it's pulled up by touchscreen press.))

Draft until patch is merged upstream, let's not merge unapproved stuff :D Upstream is stalling, the patch seems good, let's merge.