iwa: Include BDM in Single Site Settings page

This updates SiteSettingsHandler to include browsing data from BDM
in the Single Site Settings page, which currently only includes usage
from CTM.

Bug: 1311065
Change-Id: Ic18f942718b919a40679d17e61f3ec9d27c2ef94
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4339417


Reviewed-by: Christian Dullweber <dullweber@chromium.org>
Reviewed-by: Theodore Olsauskas-Warren <sauski@google.com>
Commit-Queue: Robbie McElrath <rmcelrath@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1120046}