File Upload Component Fixes (CodeQL)

[Synthereal]

PR Checklist

• Briefly describe your changes and include the issue number if it exists
• Did you build your code? (pnpm build)
• Does your code pass all tests (pnpm test)? Did you add new tests to for your changes?
• Did you add any new environment variables? If so, did you notify an admin to update infisical?
• Did you document your changes? Do you need to update any of the docs?

Changes

Refactored and fixed CodeQL security concerns for FileUpload.tsx and related components. Added proper docs as well.