UI freeze break request for Settings (port Online Accounts to GTK4)
I didn't have time to finish the review of GNOME/gnome-control-center!2039 (merged) before cutting the beta release but these changes are necessary to make gnome-control-center beta build against the latest gnome-online-accounts release (3.49.1).
Andy Holmes needs to address two small things in the MR, but other than that, it should be good to land.
These changes remove the gtk3 based helper executable we used to ship and use the new gnome-online-accounts APIs for account management.