After porting the more complex cases - in particular those that
affect a module's API - we are left with straight-forward D-Bus
method calls that can be moved to promise-based wrappers in one
go.
For consistency, this also switches from Remote to Async where
the call result is ignored.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2344>
For the screensaver service, it is quite normal that a consumer only
subscribes to the "ActiveChanged" signal without calling any methods.
The result is that we don't know about the consumer, and shut down
the service anyway after we hit the timeout.
If this happens, we break functionality like gnome-settings-daemon's
screen blanking on idle.
Fix this by simply disabling auto-shutdown for the service, which
also reflects the expectation that the screen saver service is
always running in a GNOME session.
https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/4114
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1824>