environment: Use cjs smart GObject GTypeName computation (#12453)

Make cjs to compute the GType name for registered GObject-derived
classes using the file basename and the first directory name, so that we
can avoid name clashing, and ensure that no xlet will break cinnamon by
registering a name that is already used (by cinnamon or by any other
extension).

Author: JosephMcc

js/ui/environment.js

@@ -289,6 +289,8 @@ function init() {
         St.Widget.set_default_direction(St.TextDirection.RTL);
     }
 
+    GObject.gtypeNameBasedOnJSPath = true;
+
     // Miscellaneous monkeypatching
     _patchContainerClass(St.BoxLayout);
     _patchContainerClass(St.Table);