Extend lifetime of CurrentOriginEqualsLastCommittedOrigin histogram

This is a monitoring histogram and it's still useful.

Bug: 1149516
Change-Id: I3cc1968f502f06c8ab1e42bfb39e12f95b11d50c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2541608Reviewed-by: Jesse Doherty <jwd@chromium.org>
Commit-Queue: Jesse Doherty <jwd@chromium.org>
Auto-Submit: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#828224}

tools/metrics/histograms/histograms_xml/others/histograms.xml

@@ -16246,7 +16246,7 @@ regressions. -->
 </histogram>
 
 <histogram name="Web.CurrentOriginEqualsLastCommittedOrigin"
-    enum="BooleanEqual" expires_after="2020-12-31">
+    enum="BooleanEqual" expires_after="2021-11-17">
   <owner>eugenebut@chromium.org</owner>
   <owner>gambard@chromium.org</owner>
   <summary>