Merge "Revert "Revert "Extract assistant logic from NavigationBar to share with Taskbar""" into sc-v2-dev am: 1b79c1b5ce

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/16337218

Change-Id: I3813983dd272a2853e68517e81c8ab34d5bb1b04