While we now deal more gracefully with adapter removals, we can
still mess up the hadSetupDevices tracking:
As adapters become available before any devices, we'll always
reset the setting to false when Bluetooth is turned on. And if
no set up device happens to be in range, it will still be false
when Bluetooth is turned off again.
To address that, only update the setting if we have an adapter
(like we do now) and we had one before (so it wasn't the adapter
itself that changed).
https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1174
21de88c3ba