
Since we also want to show the buttons in the calendar move the code to add buttons/actions from `MessageTray.NotificationBanner` to `Calendar.NotificationMessage`. As nothing uses custom buttons that aren't backed by actions anymore, remove that bit of the public API. Closes: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/7099 Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3173>