Extend BackgroundSync.OptionConditionsChanged UMA collection

Bug: 930926
Change-Id: I9f00d56238325d9b98b80756469ea8307b8ff594
Reviewed-on: https://chromium-review.googlesource.com/c/1488887
Auto-Submit: Rayan Kanso <rayankans@chromium.org>
Commit-Queue: Brian White <bcwhite@chromium.org>
Reviewed-by: Brian White <bcwhite@chromium.org>
Cr-Commit-Position: refs/heads/master@{#635643}

tools/metrics/histograms/histograms.xml

@@ -9874,7 +9874,7 @@ uploading your change for review.
 </histogram>
 
 <histogram name="BackgroundSync.OptionConditionsChanged"
-    enum="BooleanOptionConditionsChanged" expires_after="M74">
+    enum="BooleanOptionConditionsChanged" expires_after="M75">
   <owner>rayankans@chromium.org</owner>
   <summary>
     Whether the Background Sync dispatch conditions changed between scheduling