Update app.py

app.py

@@ -1296,7 +1296,7 @@ If you find any "Code-Blocks" then,
                 "output_json": "output_path",
                 "sprites": "result",
                 "project_output_json": "project_output",
-                "test_url": download_url
+                "test_url": "download_url"
             }), 500
         # Invoke the main agent for logic refinement and relationship identification
         # response = agent.invoke({"messages": [{"role": "user", "content": content}]})