Make Google LearnLM become Gemini model instead of PaLM2

[khfung]

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Summary

Make Google LearnLM become Gemini model instead of PaLM2
Actually should consider
} else if (model && model.includes('palm2')) {
return 'Gemini';

Change Type

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• Bug fix (non-breaking change which fixes an issue)

Testing

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Checklist

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• My code adheres to this project's style guidelines
• I have performed a self-review of my own code
• I have commented in any complex areas of my code
• My changes do not introduce new warnings
• Local unit tests pass with my changes