Integrate reset of cohort with ChromeBrowsingDataRemover

- This makes sure cohorts are reset when Cookies are cleared.
- It also sets metadata entries with source testing eligible for DTRP.
This will be best appropriate for dummy entries. This is done in this CL
to ease tag along with feature merge request.

Bug: b:335409490
Change-Id: I9e6b6bc5a4842f8fbab0d8532f0963d98ed643d7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5458857
Reviewed-by: Anton Maliev <amaliev@chromium.org>
Commit-Queue: Jonathan Njeunje <njeunje@chromium.org>
Reviewed-by: Joshua Pawlicki <waffles@chromium.org>
Reviewed-by: Christian Dullweber <dullweber@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1289485}