Use NULL for nick/blurb in GObject params

As they are only used by gstreamer for gst-inspect & other tools.
Projects like Mutter/gtk have completely dropped them as well, so follow
their path

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3505>

js/ui/workspaceAnimation.js

@@ -149,7 +149,7 @@ class WorkspaceGroup extends Clutter.Actor {
 export const MonitorGroup = GObject.registerClass({
     Properties: {
         'progress': GObject.ParamSpec.double(
-            'progress', 'progress', 'progress',
+            'progress', null, null,
             GObject.ParamFlags.READWRITE,
             -Infinity, Infinity, 0),
     },