Adjust basic Fruit Salad colors contrast

Adjust color preview mapping of fruit salad colors in revamped UI to add
more contrast.
Screenshot: https://screenshot.googleplex.com/4pKHj3bcTNSHc27.png

Bug: 275626701
Test: Manually tested on revamped and original UI
Change-Id: Ie040ab0b8ca13192ea4eae1682bfa30b8c9a9927