feat: integrate PlatformColor with alpha to replace stateLayerPressed

We're currently using a pre-computed state layer color at press opacity (0.10) used for ripple effects. It avoids runtime alpha manipulation which was incompatible with `PlatformColor` on Android before RN 0.86.
Since RN 0.86, we can now have full support for the MD3 specs + DynamicColor (`PlatformColor` + alpha).

Buttons of all kinds (regular, icon, FABs etc) are one example of components that need a custom ripple color.
The goal is to replace `ThemeColors.stateLayerPressed` with a proper ripple treatment.