Change expiry date of a histogram

Change expriy date of Apps.AppList.SearchSuccess.Apps

Bug: 1127943
Change-Id: I2bb10c24fbdcab8c80bd654082a827ea45449c04
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2500641Reviewed-by: Tony Yeoman <tby@chromium.org>
Commit-Queue: Thanh Nguyen <thanhdng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821524}

tools/metrics/histograms/histograms_xml/apps/histograms.xml

@@ -390,7 +390,7 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
 </histogram>
 
 <histogram name="Apps.AppList.SearchSuccess.Apps" enum="AppListLaunchedFrom"
-    expires_after="2020-10-29">
+    expires_after="2021-10-29">
   <owner>thanhdng@chromium.org</owner>
   <owner>jiameng@chromium.org</owner>
   <summary>