We allow this (edited)
dbus (send)
bus=session
path=/{,org/freedesktop/,org.gnome/}ScreenSaver
interface=org.freedesktop.ScreenSaver
member={Inhibit,UnInhibit,SimulateUserActivity}
peer=(label=unconfined),
As you can see the path is wrong, it should say org/gnome instead of org.gnome