
Change the dedicated Spinner widget to use the corresponding content instead of subclassing AnimatedIcon with appropriate assets. Other than the changed class hierarchy, the public API stays the same, so the impact on callers should be minimal. Closes: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/8055 Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3565>