minor #1269 Update SecurityController.php (seb-jean)

This PR was merged into the main branch.

Discussion
----------

Update SecurityController.php

I propose this PR to be in agreement with maker-bundle:
https://github.com/symfony/maker-bundle/blob/main/src/Security/SecurityControllerBuilder.php#L38

Commits
-------

38e9adb Update SecurityController.php

Author: javiereguiluz

src/Controller/SecurityController.php

@@ -36,7 +36,7 @@ class SecurityController extends AbstractController
     public function login(Request $request, Security $security, AuthenticationUtils $helper): Response
     {
         // if user is already logged in, don't display the login page again
-        if ($security->isGranted('ROLE_USER')) {
+        if ($this->getUser()) {
             return $this->redirectToRoute('blog_index');
         }