Change incorrect check for the stateless request attribute

We only want to use the session if the request is **not** `stateless`. The old code used the sesison only in `stateless` requests (so requests not intended to use the session (=state) at all).

Author: themasch

src/Symfony/Bundle/WebProfilerBundle/Controller/ProfilerController.php

@@ -180,7 +180,7 @@ public function searchBarAction(Request $request): Response
         $this->cspHandler?->disableCsp();
 
         $session = null;
-        if ($request->attributes->getBoolean('_stateless') && $request->hasSession()) {
+        if (!$request->attributes->getBoolean('_stateless') && $request->hasSession()) {
             $session = $request->getSession();
         }