Add React 19 support and fix TypeScript issues

[phDooY]

This PR adds support for React 19 and fixes several TypeScript issues:

Changes:

• Add React 19 to peerDependencies
• Update testing libraries to latest versions compatible with React 19
• Fix TypeScript errors in Dropzone component
• Improve error handling for undefined values
• Add proper type checking for File objects

All tests are passing and the package builds successfully.

Testing:

• Ran all existing tests ✅
• Built the package successfully ✅
• Verified TypeScript type checking ✅

Note: This PR maintains backward compatibility with React 17 and 18.