## Description

This fixes the handling of `dayPeriodColor` on the `TimePicker` so that if it's a non-`MaterialStateColor`, it only applies the color to the selected state, but otherwise uses the given `MaterialStateColor` to get custom behavior.

## Related Issues
 - Fixes https://github.com/flutter/flutter/issues/139445

## Tests
 - Added tests for both non-`MaterialStateColor` and `MaterialStateColor` cases.