fix: Ensure bottomSheet text is white when in dark mode

[johnhamelink]

📜 Description

Without this patch, I found that the bottom sheet text input would be black in the dark theme, just as in the light theme.

💡 Motivation and Context

It fixes the default styling of the bottom sheet in the dark theme.

💚 How did you test it?

Manual testing by alternating brightness between light & dark from flutter run.

📝 Checklist

• I reviewed submitted code
• I added tests to verify changes
• I updated the docs if needed
• All tests passing
• No breaking changes

🔮 Next steps