fix test

Author: Maxim Solovev

tests/Unit/DependencyInjection/ConfigurationTest.php

@@ -316,6 +316,7 @@ public function testSupportsAllConfigFormats(): void
                 ],
                 'throttle' => [
                     'enabled' => false,
+                    'key' => null,
                     'tokens' => 1,
                     'max_time' => null,
                 ],