js: Use async D-Bus wrappers

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>

js/ui/screenShield.js

@@ -173,7 +173,7 @@ var ScreenShield = class extends Signals.EventEmitter {
             this.emit('locked-changed');
 
         if (this._loginSession)
-            this._loginSession.SetLockedHintRemote(locked);
+            this._loginSession.SetLockedHintAsync(locked).catch(logError);
     }
 
     _activateDialog() {