Add support for fixed accent colors

[amal-stack]

Is there an existing issue for this?

• I have searched the existing issues
• I have read the guide to filing a bug

Use case

[Part of #91605 ]
Material 3 has introduced a set of new color roles that retain the same color in the light and dark themes collectively referred to as fixed accent colors See: https://m3.material.io/styles/color/the-color-system/color-roles#232e7275-6ef2-4b93-afa6-c5f76e378ced

New surface color roles have also been added: (See #137679)
These changes appear to be part of a wider set of updates to the color system, see this.

Color Roles

Fixed Accent Colors

See: https://m3.material.io/styles/color/the-color-system/color-roles#232e7275-6ef2-4b93-afa6-c5f76e378ced

Color Role	Tone: Light	Tone: Dark
Primary Fixed	P-90	P-90
Primary Fixed Dim	P-80	P-80
Secondary Fixed	S-90	S-90
Secondary Fixed Dim	S-80	S-80
Tertiary Fixed	T-90	T-90
Tertiary Fixed Dim	T-80	T-80

On Fixed Accent Colors

See: https://m3.material.io/styles/color/the-color-system/color-roles#6a242aff-e606-43d5-a7de-988facc90968

Color Role	Tone: Light	Tone: Dark
On Primary Fixed	P-10	P-10
On Primary Fixed Variant	P-30	P-30
On Secondary Fixed	S-10	S-10
On Secondary Fixed Variant	S-30	S-30
On Tertiary Fixed	T-10	T-10
On Tertiary Fixed Variant	T-30	T-30

Proposal

Update ColorScheme to include the above roles. The current ColorScheme.fromSeed implementation uses the Scheme class underneath which is planned to be deprecated. For more info, see #137679.