Phone Hub: Modify Phone Hub tray to show nudge.

Modify Phone Hub tray methods to display Phone Hub nudge if nudge flag is on. Also, hide the nudge when Phone Hub icon is clicked.

UI:
(Recording of nudge being hidden after clicking on Phone Hub icon)
https://drive.google.com/file/d/1P9yVCb-aRB7IXY2gqHhorPFXbojnpckz/view?usp=sharing
https://screenshot.googleplex.com/6DLVFX739n9Us6a

Change-Id: I81ea423963ce395521e749a96b0ac7db33474020
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4163684


Commit-Queue: Jennifer Serrano <jennserrano@google.com>
Reviewed-by: Jon Mann <jonmann@chromium.org>
Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1098164}