Explictly enable property access in the tests (related to https://github.com/symfony/symfony/pull/40140, it is a dev dependency)

Tests/Functional/TestKernel.php

@@ -126,6 +126,7 @@ class TestKernel extends Kernel
             'validation' => null,
             'form' => null,
             'serializer' => ['enable_annotations' => true],
+            'property_access' => true,
         ];
 
         $c->loadFromExtension('framework', $framework);