Support numeric fileSize in FullscreenImageCarousel

[qroll]

Type of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing apis or functionality to change)
• Documentation (change to documentation, comments or API descriptions)
• Tests (improvements to unit tests or E2E tests)
• Other (technical improvements, refactoring, or changes that don't fall into the above categories)

Description of changes

• Small QoL change, noticed that consumer had to reimplement the file size formatting logic in their application
• Reuses the existing display formatter as with FileDownload

Checklist

• Changes follow the project guidelines in CONTRIBUTING.md and CONVENTIONS.md
• Looks good on mobile and tablet
• Updated documentation
• Added/updated unit tests
• Added/updated E2E tests visual display covered in FullscreenImageCarousel-Carousel-with-file-data--mount.png, logic covered by unit tests