Change colors shown in Gesture Nav Tutorial for light mode

We use a second set of colors to ensure that the text is more visible in light mode for the gesture navigation tutorial.

Fix: 318471359
Test: Run the gesture navigation tutorial in light mode and dark mode
Flag: LEGACY ENABLE_NEW_GESTURE_NAV_TUTORIAL ENABLED
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:58aacfad2b478c26d73276ba78d5d3388ec5ddc2)
Merged-In: Ib83fdcce1d2bd057ca4bf3258cc81fda704bf149
Change-Id: Ib83fdcce1d2bd057ca4bf3258cc81fda704bf149