cros: Update 'user icon' to an icon with no hair

UX prefers the more neutral look

Screenshot: https://screenshot.googleplex.com/3VGcrnkAy773oBg.png

Bug: b:284330163
Change-Id: I28e4f09048be8760491c4b099fdf45262beb27f5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4568213


Commit-Queue: Alex Newcomer <newcomer@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Commit-Queue: James Cook <jamescook@chromium.org>
Auto-Submit: Alex Newcomer <newcomer@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1152631}