node: "Load Upscale Model" - add "MODEL_NAME"

### Feature Idea

It would be nice to expand the node with the RETURN_TYPES = ("UPSCALE_MODEL", "STRING") parameters so that the model name can be added to the file name later.

### Existing Solutions

tmp-example from DeepSeek ( C:\ComfyUI\ComfyUI\custom_nodes )
I use this in my workflows

[spandrel_loader.py](https://github.com/user-attachments/files/25288362/spandrel_loader.py)

### Other

_No response_

Start with the attached spandrel_loader.py example and locate the existing "Load Upscale Model" node in ComfyUI. Confirm how the node currently returns its upscale model, then make the requested output include UPSCALE_MODEL and STRING so the model name is available for later filename use.

Written by the indexing model from the issue text.