Use gtk_accessible_announce when there is an undergoing action
Aka when something is loading.
This is a new API introduced in GTK 4.14, to make the screen reader read messages according to given priorities.
It would also be useful to use that method for toasts, but there is already an issue upstream: GNOME/libadwaita#829. We will need to watch it to see if there is anything to do on our end when it is fixed.