ash: Use mojo LocaleNotificationController interface.

ash/mus/manifest.json

 {
   "manifest_version":  1,
   "name": "service:ash",
   "display_name": "Ash Window Manager and Shell",
   "capabilities": {
     "provided": {
       "ash": [
+        "ash::mojom::LocaleNotificationController",
         "ash::mojom::ShelfController",
         "ash::mojom::SystemTray",
         "ash::mojom::WallpaperController"
       ],
       "mus:window_manager" : [ "ui::mojom::AcceleratorRegistrar" ]
     },
     "required": {
       "*": [ "accessibility", "app" ],
       "service:content_browser" : [ "content_browser:ash" ],
       "service:mash_session": [ "mash_session:session" ],
       "service:ui": [ "ui:window_manager" ],
       "service:touch_hud": [ "mash:launchable" ]
     }
   }
 }