NavigationThrottle: Extend RedirectCoount metrics

The PolicyBlocklist related experiment was already done,
and the new optimization was already rolled out.
But as the redirect count data still needs some
investigations, I will extend the expiry date by 1Q.

Bug: 398847612
Fixed: 398847612
Change-Id: I6a3c30fda4cc3c82f3e36e7037b5fcfac8d62c27
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6301499
Commit-Queue: Minoru Chikamune <chikamune@chromium.org>
Auto-Submit: Takashi Toyoshima <toyoshim@chromium.org>
Reviewed-by: Minoru Chikamune <chikamune@chromium.org>
Commit-Queue: Takashi Toyoshima <toyoshim@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1424345}