Split complex method Issues::UpdateService#execute

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/services/issues/update_service.rb

@@ -22,6 +22,15 @@ module Issues
             issue, issue.labels - old_labels, old_labels - issue.labels)
         end
 
+        handle_changes(issue)
+        issue.create_new_cross_references!(current_user)
+        execute_hooks(issue, 'update')
+      end
+
+      issue
+    end
+
+    def handle_changes(issue)
       if issue.previous_changes.include?('milestone_id')
         create_milestone_note(issue)
       end
@@ -34,12 +43,6 @@ module Issues
       if issue.previous_changes.include?('title')
         create_title_change_note(issue, issue.previous_changes['title'].first)
       end
-
-        issue.create_new_cross_references!(current_user)
-        execute_hooks(issue, 'update')
-      end
-
-      issue
     end
   end
 end