workspacesView: Use work area for default geometry

The workspace's layout manager keeps the workspace at the same ratio as
the work area, so it makes more sense to base the views' default geometry
on that as well than the monitor area we are using right now.

(It shouldn't matter much in practice, as this only affects views on
non-primary monitors where the work area usually matches the monitor area)

https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1345

js/ui/workspacesView.js

@@ -22,7 +22,7 @@ var WorkspacesViewBase = GObject.registerClass({
 }, class WorkspacesViewBase extends St.Widget {
     _init(monitorIndex) {
         const { x, y, width, height } =
-            Main.layoutManager.monitors[monitorIndex];
+            Main.layoutManager.getWorkAreaForMonitor(monitorIndex);
 
         super._init({
             style_class: 'workspaces-view',