Update JetMoe model card

[Tolu-Oye]

What does this PR do?

This PR replaces the JetMoe model card with a new model card matching the format introduced in #36979.

Note: The attention mask image link is currently blank because the image has not been uploaded yet. I will update it once the dataset PR is merged.

Fixes # (issue)

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
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• Did you make sure to update the documentation with your changes? Here are the
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  here are tips on formatting docstrings.
• Did you write any new necessary tests?

Who can review?

@stevhliu

[Tolu-Oye]

@stevhliu, I pinged you to merge the attention visualizer image on the hugging face website. I think that's what I'm supposed to do, so let me know if that's not the case.

[stevhliu]

Thank you so much for the time and effort you put into this—I really appreciate it. With the number of models in Transformers growing so quickly, I’ve been looking into ways to automate model card generation to keep up with the pace. For now, I’ll be closing this PR, but I’m very grateful for your interest in this project!

Thanks again 🤗