[bookmarks] Unexpire Bookmarks.Count.OnProfileLoad

The metrics continue to be useful.

Change-Id: If2a5c82258c42cf44ab5d6508fd41a246b89c2de
Fixed: 1368164
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4350272


Commit-Queue: Mark Pearson <mpearson@chromium.org>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Auto-Submit: Mikel Astiz <mastiz@chromium.org>
Commit-Queue: Mikel Astiz <mastiz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1118884}