Update the spelling of the word "optionnal" to "optional" in 4 places.
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## Summary by CodeRabbit
- **New Features**
- Made the file type selection optional in the file upload feature.
- **Bug Fixes**
- Addressed issues with color mode synchronization, persistence, and
user reset behavior.
- Improved caching and bundling of files.
- **Documentation**
- Corrected spelling errors and typos in various documentation files for
better clarity and accuracy.
- **Style**
- Updated admin display labels for enhanced clarity.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
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Co-authored-by: Baptiste Arnaud <baptiste.arnaud95@gmail.com>
