Introduce NICViewModel#iconColors

This CL replaces the older tint calculation logic used for AOD and
status bar notification icons with a new Recommended Architecture stack.

Flag: NOTIFICATION_ICON_CONTAINER_REFACTOR
Bug: 290787599
Bug: 278765923
Test: atest SystemUITests
Change-Id: Ie8cf64c103e5e4fa99dc499a3eaa8bd18ab6f609