temp/mutter-mobile: remove zenity dependency
mutter no longer depends on zenity as of version 43.alpha.
See https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2370 And https://gitlab.gnome.org/GNOME/mutter/-/blob/e331e38a191a36faaa5bb049157ab77f94fd7654/NEWS#L137
Alpine commit: https://gitlab.alpinelinux.org/alpine/aports/-/commit/80c64759d16d1161ba706f83fca4d7518ebc3302