Update locale with new authentication system

For the new authentication system, the LoginSuccessEvent event that is fired after logging in. This is to be updated in the new documentation

Author: r-ant-2468

session/locale_sticky_session.rst

@@ -148,8 +148,7 @@ event::
 
     use Symfony\Component\EventDispatcher\EventSubscriberInterface;
     use Symfony\Component\HttpFoundation\RequestStack;
-    use Symfony\Component\Security\Http\Event\InteractiveLoginEvent;
-    use Symfony\Component\Security\Http\SecurityEvents;
+    use Symfony\Component\Security\Http\Event\LoginSuccessEvent;
 
     /**
      * Stores the locale of the user in the session after the
@@ -164,19 +163,19 @@ event::
             $this->requestStack = $requestStack;
         }
 
-        public function onInteractiveLogin(InteractiveLoginEvent $event)
+        public function onLoginSuccess(LoginSuccessEvent $event): void
         {
-            $user = $event->getAuthenticationToken()->getUser();
+            $user = $event->getUser();
 
             if (null !== $user->getLocale()) {
                 $this->requestStack->getSession()->set('_locale', $user->getLocale());
             }
         }
 
-        public static function getSubscribedEvents()
+        public static function getSubscribedEvents(): array
         {
             return [
-                SecurityEvents::INTERACTIVE_LOGIN => 'onInteractiveLogin',
+                LoginSuccessEvent::class => 'onLoginSuccess',
             ];
         }
     }