N°6934 - Symfony 6.4 - upgrade Symfony bundles to 6.4 (#580)

* Update Symfony lib to version ~6.4.0
* Update code missing return type
* Add an iTop general configuration entry to store application secret (Symfony mandatory parameter)
* Use dependency injection in ExceptionListener & UserProvider classes

lib/symfony/cache/Traits/ProxyTrait.php

@@ -21,20 +21,14 @@ use Symfony\Contracts\Service\ResetInterface;
  */
 trait ProxyTrait
 {
-    private $pool;
+    private object $pool;
 
-    /**
-     * {@inheritdoc}
-     */
-    public function prune()
+    public function prune(): bool
     {
         return $this->pool instanceof PruneableInterface && $this->pool->prune();
     }
 
-    /**
-     * {@inheritdoc}
-     */
-    public function reset()
+    public function reset(): void
     {
         if ($this->pool instanceof ResetInterface) {
             $this->pool->reset();