[iOS] Updates expiry of Download.IOSDownloadFileUIGoogleDrive histogram

This CL postpones the expiration of a year.

Bug: 1140087
Change-Id: I58bccf3917e9e6edd3effc629918fcee44c643b6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2502336
Auto-Submit: Ewann Pellé <ewannpv@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@{#821987}

tools/metrics/histograms/histograms_xml/download/histograms.xml

@@ -333,7 +333,7 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
 </histogram>
 
 <histogram name="Download.IOSDownloadFileUIGoogleDrive"
-    enum="DownloadFileUIGoogleDrive" expires_after="2020-11-29">
+    enum="DownloadFileUIGoogleDrive" expires_after="2021-11-29">
   <owner>ewannpv@chromium.org</owner>
   <owner>eugenebut@chromium.org</owner>
   <summary>