PLT-3631 Properly update PostViewController when emojis change (#3565)

* Properly remove custom emojis from clientside store

* Properly update PostViewController when emojis change

webapp/components/post_view/post_view_controller.jsx

@@ -247,6 +247,10 @@ export default class PostViewController extends React.Component {
             return true;
         }
 
+        if (nextState.emojis !== this.state.emojis) {
+            return true;
+        }
+
         return false;
     }