js: Queue 'later' via MetaLaters

This replaces the meta_later_add() API which used now removed global
singletons under the hood.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2557>

js/gdm/authList.js

@@ -112,7 +112,8 @@ var AuthList = GObject.registerClass({
 
         let focusSet = this.navigate_focus(null, St.DirectionType.TAB_FORWARD, false);
         if (!focusSet) {
-            Meta.later_add(Meta.LaterType.BEFORE_REDRAW, () => {
+            const laters = global.compositor.get_laters();
+            laters.add(Meta.LaterType.BEFORE_REDRAW, () => {
                 this._moveFocusToItems();
                 return false;
             });