Separate color into app color and dot color; specify dot color

Design intends for predicted app disc to use the app color, and the
dot to use tertiary T90/shade100. Both currently use `color`. Separating
into two separate colors lets use define the two separate colors
requested by design.

Bug: 213314628
Test: Manual inspection at runtime
Change-Id: If50c32d0bf67493192ce32a33775311d58f21942