Adding a <dbus/> element containing a boolean (yes/no) determines
whether org.gnome.Mutter.DisplayConfig ApplyMonitorsConfig will be
callable. The state is also introspectable via the
ApplyMonitorsConfigAllowed property on the same interface.
For example
<monitors version="2">
<policy>
<dbus>no</dbus>
</policy>
</monitors>
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2030>
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