preload: Extend the expiry date of
Bookmarks.BookmarkBar.NavigationOrActivationToFirstMeaningfulPaint

Extend the expiry date of the metrics as the metrics are still in used
for evaluating the performance of prerender BookmarkBar trigger.

Bug: 407543740
Change-Id: I6e69f7cd265f80b19c63ed75a4ef47f74f265fee
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6420544
Commit-Queue: Huanpo Lin <robertlin@chromium.org>
Reviewed-by: Emily Shack <emshack@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1441298}