Setting preview method via command line args breaks previews in custom samplers and other 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

command line argument affecting only default nodes.

### Actual Behavior

command line argument affecting custom nodes.

### Steps to Reproduce

try with WanVideoWrapper nodes for example. WanVideo Sampler gets broken. Also VideoCombine nodes get broken.

### Debug Logs

```powershell
it doesnt report any errors related to the issue.
```

### Other

_No response_