This PR is to introduce 19 new color roles and deprecate 3 color roles in `ColorScheme`.
**Tone-based surface colors** (7 colors): 
* surfaceBright
* surfaceDim
* surfaceContainer
* surfaceContainerLowest
* surfaceContainerLow
* surfaceContainerHigh
* surfaceContainerHighest

**Accent color add-ons** (12 colors):
* primary/secondary/tertiary-Fixed
* primary/secondary/tertiary-FixedDim
* onPrimary/onSecondary/onTertiary-Fixed
* onPrimary/onSecondary/onTertiary-FixedVariant

**Deprecated colors**:
* background -> replaced with surface
* onBackground -> replaced with onSurface
* surfaceVariant -> replaced with surfaceContainerHighest

Please checkout this [design doc](https://docs.google.com/document/d/1ODqivpM_6c490T4j5XIiWCDKo5YqHy78YEFqDm4S8h4/edit?usp=sharing) for more information:)

![Screenshot 2024-01-08 at 4 56 51 PM](https://github.com/flutter/flutter/assets/36861262/353cdb4c-6ba9-4435-a518-fd3f67e415f0)