Extend histogram expiration milestone

Bug: 1138316, 1138317
Change-Id: Ib2ce5f4114643e3e463f413bd01cd0934d00c3ea
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2512897
Auto-Submit: Rayan Kanso <rayankans@chromium.org>
Reviewed-by: Caitlin Fischer <caitlinfischer@google.com>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Commit-Queue: Ilya Sherman <isherman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#823261}

tools/metrics/histograms/histograms_xml/service/histograms.xml

@@ -182,7 +182,7 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
 </histogram>
 
 <histogram name="ServiceWorker.ContentDeleteEvent.Time" units="ms"
-    expires_after="M88">
+    expires_after="M92">
   <owner>rayankans@chromium.org</owner>
   <owner>platform-capabilities@chromium.org</owner>
   <summary>
@@ -709,7 +709,7 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
 </histogram>
 
 <histogram name="ServiceWorker.PushSubscriptionChangeEvent.Time" units="ms"
-    expires_after="M88">
+    expires_after="M92">
   <owner>peter@chromium.org</owner>
   <owner>rayankans@chromium.org</owner>
   <owner>knollr@chromium.org</owner>