[enhancement]: Retain model default settings when converting to diffusers

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Contact Details

shanedk

### What should this feature add?

When converting a checkpoint model to diffusers, if the user has set model defaults, they should be copied to the new diffusers model before the checkpoint is deleted.

Otherwise, the user is left having to remember the settings and put them back in. They could preemptively write them down, but only if they know ahead of time the settings will be lost. Far better for Invoke to simply copy them over after conversion.

### Alternatives

_No response_

### Additional Content

_No response_