GNOME Software no longer has a welcome screen in any current
Fedora (it was dropped between 35 and 36), but in Rawhide it now
has a popup that prompts you to enable third-party repos which
we need to get rid of, so just convert the welcome screen check
to handle that, and drop all the welcome screen needles.
Signed-off-by: Adam Williamson <awilliam@redhat.com>
