Fix: ensure repr_mimebundle handles empty include/exclude parameters gracefully

[alonsosilvaallende]

📝 Summary

Closes #7786
I have followed the recommendations by @xflr6

🔍 Description of Changes

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Project	Deployment	Review	Updated (UTC)
marimo-docs	Ready	Preview, Comment	Jan 13, 2026 9:42am

[alonsosilvaallende]

I have read the CLA Document and I hereby sign the CLA

[mscolnick]

@alonsosilvaallende would it be possible to add a small test for this so we don't regress it?

[akshayka]

Thanks so much for the fix, @alonsosilvaallende. I have left one comment

[alonsosilvaallende]

Sure, I have added the required tests @mscolnick

[github-actions]

🚀 Development release published. You may be able to view the changes at https://marimo.app?v=0.19.3-dev19