Update Gradio_UI.py

Gradio_UI.py

@@ -133,9 +133,9 @@ def launch_step_by_step_ui():
             file_path = None
             if isinstance(updated_state, dict) and updated_state.get("done"):
                 file_path = updated_state["pdf"]
-                restart_button.visible = True
+                return messages, updated_state, file_path
 
-            return messages, updated_state, file_path
+            return messages, updated_state, None
 
         def restart_conversation():
             return [initial_message], {"step": 0, "answers": {}}, None