cleanup: Remove spaces in object literals

We only adopted this style relatively recently, so there's a bit
more to adjust. Still, it's manageable and another step towards
getting rid of the legacy style.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2866>

js/ui/osdMonitorLabeler.js

@@ -12,7 +12,7 @@ import * as Main from './main.js';
 const OsdMonitorLabel = GObject.registerClass(
 class OsdMonitorLabel extends St.Widget {
     _init(monitor, label) {
-        super._init({ x_expand: true, y_expand: true });
+        super._init({x_expand: true, y_expand: true});
 
         this._monitor = monitor;