Remove jitter on verifying/unverifying safety number

On every click, even when sub-panes were open, we were calling
markRead(), which would save the conversation model with the new
unreadCount. The KeyVerificationPanelView was wired up to the change
event on conversation, so it would render with the results of that
update, then finally the user's intended update.

FREEBIE

js/views/conversation_view.js

@@ -252,8 +252,6 @@
             } else if (this.banner) {
                 this.banner.remove();
                 this.banner = null;
-
-                // TODO: Is there anything else we should do here? make messages re-send-able?
             }
         },
 
@@ -533,8 +531,11 @@
         },
 
         onClick: function(e) {
-            this.closeMenu(e);
-            this.markRead();
+            // If there are sub-panels open, we don't want to respond to clicks
+            if (!this.panels || !this.panels.length) {
+                this.closeMenu(e);
+                this.markRead();
+            }
         },
 
         findNewestVisibleUnread: function() {