Make DummyObject more robust (#20146)

src/transformers/utils/import_utils.py

@@ -986,9 +986,9 @@ class DummyObject(type):
     `requires_backend` each time a user tries to access any method of that class.
     """
 
-    def __getattr__(cls, key):
+    def __getattribute__(cls, key):
         if key.startswith("_"):
-            return super().__getattr__(cls, key)
+            return super().__getattribute__(key)
         requires_backends(cls, cls._backends)