feat(color): add new colors and schema tokens in Teams theme

[mnajdova]

Added new brand and onyx colors and background4 token for default and brand color schemes.

[codecov]

Codecov Report

Merging #1581 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1581   +/-   ##
=======================================
  Coverage   71.53%   71.53%           
=======================================
  Files         847      847           
  Lines        6931     6931           
  Branches     1997     1977   -20     
=======================================
  Hits         4958     4958           
  Misses       1967     1967           
  Partials        6        6

Impacted Files	Coverage Δ
packages/react/src/themes/teams/colors.ts	76.47% <ø> (ø)	⬆️
packages/react/src/themes/teams-dark/colors.ts	100% <ø> (ø)	⬆️
...ges/react/src/themes/teams-high-contrast/colors.ts	100% <ø> (ø)	⬆️

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