birch: Connect BirchMostVisitedItem to history service and favicon

Birch shows a suggestion chip for the most visited URL. The URL comes
from the history service and the favicon comes from the favicon
service. The URL is de-duplicated with recent tab URLs at the
BirchModel layer.

Bug: b:340346995
Test: ash_unittests and unit_tests
Change-Id: Ic1305b1d450219ad351ba5d50f211820fdcfd256
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5555663
Commit-Queue: James Cook <jamescook@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Matthew Mourgos <mmourgos@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1305428}