feat: expose UiNotifications service (#1172)

* playing around

* Change extension init and preRegistration signature

* Clear test code

* Update core index test

* Fix test

* Tricking the bug

* Renaming file back to trick some weird bug

extensions/_example/src/index.js

@@ -11,7 +11,7 @@ export default {
    * LIFECYCLE HOOKS
    */
 
-  preRegistration(extensionConfiguration) {},
+  preRegistration({ serviceManager, configuration: extensionConfiguration }) {},
 
   /**
    * MODULE GETTERS