Delay expiry of policy histograms.

Delay expiry of PolicyUpdatePeriod.Device and
PolicyUpdatePeriod.User.

Bug: chromium:1165053
Change-Id: I8b2d8cb4d009bbb7d0fce0c667f0d3eabf21e2ec
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2635151Reviewed-by: Caitlin Fischer <caitlinfischer@google.com>
Commit-Queue: Victor-Gabriel Savu <vsavu@google.com>
Cr-Commit-Position: refs/heads/master@{#844574}

tools/metrics/histograms/histograms_xml/enterprise/histograms.xml

@@ -1064,7 +1064,7 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
 </histogram>
 
 <histogram name="Enterprise.PolicyUpdatePeriod.Device" units="days"
-    expires_after="M90">
+    expires_after="M95">
   <owner>rbock@google.com</owner>
   <owner>igorcov@chromium.org</owner>
   <summary>Time since last device policy fetch.</summary>
@@ -1078,7 +1078,7 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
 </histogram>
 
 <histogram name="Enterprise.PolicyUpdatePeriod.User" units="days"
-    expires_after="M90">
+    expires_after="M95">
   <owner>rbock@google.com</owner>
   <owner>igorcov@chromium.org</owner>
   <summary>Time since last user policy fetch.</summary>