Revert "Add API to let apps color CallStyle notifications themse..."

Revert "Add CTS tests for CallStyle, including setting color hints."

Revert submission 13661867-call_style_colors

Reason for revert: Possible culprit of b/181087733
Reverted Changes:
I537191e7c:Add API to let apps color CallStyle notifications ...
I8bd00b8c2:Add CTS tests for CallStyle, including setting col...

Change-Id: Ia8699f6ef151000212606bea598a2abefa6b53a7