
The parameter used to be optional until commit d54219c0982, but after GObjectifaction `undefined` is no longer interchangeable with `null` here. Restore the old behavior, as it's used by extensions (including one of our own templates). Closes: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/8068 Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3548>