This means gnomeshell_dbusrunner.py only need to bother with arguments it needs to care about, which currently are none. Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3455>
This adds a dbus-runner ala meta-dbus-runner.py. It extends the one used in mutter, and adds various mocked services needed by gnome-shell. Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1349>