Clear template cache when authenticating OIDC usr

Address OIDC authentication issue where cached menu templates are not
refreshed on login.

When a user's groups are updated in the identity provider, this fix
ensures that the main menu icons are updated to show all admin functions.

plugins/arOidcPlugin/lib/oidcUser.class.php

@@ -183,6 +183,11 @@ public function authenticate($username = null, $password = null): bool
             }
 
             $authenticated = true;
+
+            // Clear template cache.
+            $cacheClear = new sfCacheClearTask(sfContext::getInstance()->getEventDispatcher(), new sfFormatter());
+            $cacheClear->run([], ['type' => 'template']);
+
             // Refresh user so new groups and credentials are immediately available on signIn().
             $this->signIn(QubitUser::getById($user->id));
         }