Bump @fortawesome/fontawesome-free from 5.11.2 to 5.15.2

Bumps [@fortawesome/fontawesome-free](https://github.com/FortAwesome/Font-Awesome) from 5.11.2 to 5.15.2.
- [Release notes](https://github.com/FortAwesome/Font-Awesome/releases)
- [Changelog](https://github.com/FortAwesome/Font-Awesome/blob/master/CHANGELOG.md)
- [Commits](FortAwesome/Font-Awesome@5.11.2...5.15.2)

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