[UMA] Change histogram expiry milestone

Bug: 1138279
Change-Id: I39b513667cec27eecd02920bd5148b10d087b844
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2490968Reviewed-by: Jesse Doherty <jwd@chromium.org>
Commit-Queue: Alex Danilo <adanilo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#820109}

tools/metrics/histograms/histograms_xml/file/histograms.xml

@@ -241,7 +241,7 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   </summary>
 </histogram>
 
-<histogram name="FileBrowser.Load" units="ms" expires_after="M88">
+<histogram name="FileBrowser.Load" units="ms" expires_after="M92">
   <owner>slangley@chromium.org</owner>
   <owner>weifangsun@chromium.org</owner>
   <summary>