Merge "Set navigation mode when taskbar is initialised." into sc-v2-dev am:...

Merge "Set navigation mode when taskbar is initialised." into sc-v2-dev am: 28576187 am: 0164a77e

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15853555

Change-Id: Ief294fef320c669d815efb49dd26047d5ec811a8