"Load workflow" is disabled when submitting prompt via API

### Expected Behavior

when a API workflow is queued via the API endpoint it should be possible to open it normally like any other workflow which was queued from within ComfyUI.

### Actual Behavior

"Load workflow" is disabled

once the image is generated I can just drag it into Comfy and see the workflow

### Steps to Reproduce

1. download [default_api.json](https://github.com/user-attachments/files/19336823/default_api.json) (default workflow with "Export API" and steps=1000. you might need to change the model filename.)
2. ```$ curl -X POST -H "Content-Type: application/json" -d "{\"prompt\": $(cat default_api.json), \"client_id\": \"me\"}" http://127.0.0.1:8188/prompt```
3. go to http://127.0.0.1:8188/?client_id=me
4. open queue and right-click "Load workflow"

### Debug Logs

```powershell
got prompt
{"prompt_id": "def06b1f-6e6f-4770-9833-8d09c4ab0160", "number": 6, "node_errors": {}}
```

### Other

_No response_