Update the strings in the gesture nav tutorial

Change the strings for the instructions and feedback for the gesture navigation tutorial to align with new UX changes.

Flag: ENABLE_NEW_GESTURE_NAV_TUTORIAL
Fix: 286547594
Test: Manually went through the redesigned tutorial and verified that
the new strings correctly show up. Also checked that the previous
tutorial remains unchanged.

Change-Id: I27a3e8c0f09e7755e6087ce5b004b687f229d153