data: Wait for systemd-udev-settle.service
Seems like some distributions (i.e. Arch) try to be smart and cause DRM modules to be loaded/probed late during boot. This in turn can lead to GDM starting too early, and then either failing completely or falling back to X11.
While technically deprecated, we really need to have the drm devices resolved when we try to start GNOME Shell. This is the straight forward way of ensuring that is the case.
It might be possible to be a bit smarter here by watching udev and checking whether a DRM device is available for each seat.
Closes: #662 (closed)