[enhancement]: Mark cached models in the dropdown list

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Contact Details

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### What should this feature add?

It would be helpful to display differently in the dropdown menu models that have already be converted to Diffusers and cached locally. Maybe making them Bold, or adding a symbol next to the name.. something like that.
Selecting a model that has not been converted yet can take several minutes and really break the flow.

### Alternatives

_No response_

### Additional Content

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