feat: add navigationBarTranslucent prop for Android navigation bar support

[Sameed1998]

Description

This PR adds support for navigationBarTranslucent prop to handle Android navigation bar transparency in the dropdown modal.

Changes Made

• Added navigationBarTranslucent prop to SelectDropdown component
• Updated TypeScript definitions in index.d.ts with proper JSDoc comments
• Modified DropdownModal component to accept and pass the new prop to React Native's Modal
• Enhanced prop passing from SelectDropdown → DropdownModal → Modal component

Technical Details

• New prop: navigationBarTranslucent?: boolean
• Default value: false (maintains backward compatibility)
• Follows same pattern as existing statusBarTranslucent prop
• Properly typed with TypeScript definitions

Use Case

This feature is useful for Android apps that use translucent navigation bars, allowing the dropdown modal to properly handle the navigation bar area.

Backward Compatibility

• ✅ Existing code will work without any changes
• ✅ New prop is optional with sensible default
• ✅ No breaking changes

Files Modified

• src/SelectDropdown.js - Added prop parameter and passing
• src/components/DropdownModal.js - Added prop handling and Modal integration
• index.d.ts - Added TypeScript definition with documentation

Testing

• Verified TypeScript compilation
• Confirmed backward compatibility
• Tested prop passing through component chain