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/config/ConfigCache.php

@@ -25,7 +25,7 @@ use Symfony\Component\Config\Resource\SelfCheckingResourceChecker;
  */
 class ConfigCache extends ResourceCheckerConfigCache
 {
-    private $debug;
+    private bool $debug;
 
     /**
      * @param string $file  The absolute cache path
@@ -48,10 +48,8 @@ class ConfigCache extends ResourceCheckerConfigCache
      *
      * This implementation always returns true when debug is off and the
      * cache file exists.
-     *
-     * @return bool
      */
-    public function isFresh()
+    public function isFresh(): bool
     {
         if (!$this->debug && is_file($this->getPath())) {
             return true;