Fix display of related changes

The fix for displaying submitted together changes didn't update the
observer for related changes, so fixing one thing broke the other. This
change corrects that, and observes related changes in the same manner as
submitted together changes.

Bug: Issue 10003
Change-Id: I4b8e3b229c14cda8a5e28a376e58e976d8a3349d
diff --git a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.js b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.js
index f2cfe87..39f4d8d 100644
--- a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.js
+++ b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.js
@@ -82,7 +82,7 @@
     ],
 
     observers: [
-      '_resultsChanged(_relatedResponse.changes, _submittedTogether, ' +
+      '_resultsChanged(_relatedResponse, _submittedTogether, ' +
           '_conflicts, _cherryPicks, _sameTopic)',
     ],