0.3.67 Breaks pnginfo and downstream custom image save nodes

### Custom Node Testing

- [ ] I have tried disabling custom nodes and the issue persists (see [how to disable custom nodes](https://docs.comfy.org/troubleshooting/custom-node-issues#step-1%3A-test-with-all-custom-nodes-disabled) if you need help)

### Expected Behavior

I use a custom node to add extra metadata to PNG files so they are compatible with CivitAI resources autodetection.

This node adds LoRA and Prompt info to the PNG file including special formatting for CivitAI

### Actual Behavior

After upgrading to 0.3.67 core, this node stopped working generating an error message that the prompt and lora information was no longer available in the pnginfo_dict

### Steps to Reproduce

Save image with custom node
upload to CivitAI
CivitAI does not recognize Prompt or Lora or Model info

### Debug Logs

```powershell
[ComfyUI Image Metadata Extension] WARNING: Positive prompt is empty!
[ComfyUI Image Metadata Extension] WARNING: Steps are empty, full metadata won't be added!
[ComfyUI Image Metadata Extension] WARNING: Seed not found in pnginfo_dict!
```

### Other

Node is
ComfyUI Image Metadata Extension

https://github.com/edelvarden/comfyui_image_metadata_extension