Extend expiration of PageLoad.Internal.PageLoadTimingStatus histograms

These histograms are used for internal debugging purposes to understand
the page load and metric records availability. We need to continue to
monitor this to ensure these records remain correct, and to debug any
issues.

This CL increases the expiry by ~1 year.

Change-Id: I7663c414b5f14e45ccd473ce9c6fec448d757f9d
Fixed: 436260038
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6819890
Reviewed-by: Shunya Shishido <sisidovski@chromium.org>
Commit-Queue: Takashi Toyoshima <toyoshim@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1497377}