fix bug with serving burger

overcooked_simulator/counters.py

@@ -145,7 +145,7 @@ class ServingWindow(Counter):
         ):
             if isinstance(item.content, Meal) and item.content.progressed_steps:
                 return item.content.finished
-            if not item.item_info.steps_needed and len(
+            if not item.content.item_info.steps_needed and len(
                 item.content.item_info.needs
             ) == len(item.content.parts):
                 return True