Image Generation Pro 3 model error

## Describe the bug
When i use Image generator and select Pro 3 model, it throw the error-

CLIPLoader: MistralConverter.__init__() missing 1 required positional argument: 'vocab_file'
I don't exactly know how to solve the issue so i hope it can be fixed by you guys.

## Expected behavior

I hope the Pro 3 image generation can work again

## Screenshots

## Environment (please complete the following information):

- OS: Windows 11 Build 26200.9168
- GPU: GeForce RTX 5060 Laptop GPU
- CPU: Ryzen 9 8940HX
- Version: 3.20 BETA

## Additional context

I have tried to reinstall the app, test on other device but i think the problem is universal. Additionally that Pro 2 image model works =)

Thank you

Start by reproducing the failure in AI Playground 3.20 BETA on the Pro 3 model and compare it with the working Pro 2 model. Use the reported CLIPLoader and MistralConverter error as the initial trace point; done means Pro 3 image generation works again without the missing vocab_file error.

Written by the indexing model from the issue text.