Update Gesture/3B nav color to B/W

Initial screenshot tests for bubblesfor edge-to-edge efforts, we are making e2e platform defaults but want to ensure that there is sufficient background protection / small icons like status bar & 3 button nav icons have max contrast.

Flag: EXEMPT bugfix
Bug: 323575750
Test: Manual
Change-Id: I9f5c83e892a8ad9c717f062cef0459739dafd44e