Fix Psalm errors

Author: fabpot

Authentication/CustomAuthenticationSuccessHandler.php

@@ -37,7 +37,7 @@ public function __construct(AuthenticationSuccessHandlerInterface $handler, arra
         }
     }
 
-    public function onAuthenticationSuccess(Request $request, TokenInterface $token): Response
+    public function onAuthenticationSuccess(Request $request, TokenInterface $token): ?Response
     {
         return $this->handler->onAuthenticationSuccess($request, $token);
     }

Authentication/DefaultAuthenticationSuccessHandler.php

@@ -52,7 +52,7 @@ public function __construct(HttpUtils $httpUtils, array $options = [], LoggerInt
         $this->setOptions($options);
     }
 
-    public function onAuthenticationSuccess(Request $request, TokenInterface $token): Response
+    public function onAuthenticationSuccess(Request $request, TokenInterface $token): ?Response
     {
         return $this->httpUtils->createRedirectResponse($request, $this->determineTargetUrl($request));
     }