Fixing new messages indicator (#4531)

webapp/utils/constants.jsx

@@ -70,6 +70,7 @@ export const ActionTypes = keyMirror({
 
     RECEIVED_CHANNELS: null,
     RECEIVED_CHANNEL: null,
+    RECEIVED_CHANNEL_MEMBER: null,
     RECEIVED_MORE_CHANNELS: null,
     RECEIVED_CHANNEL_STATS: null,
     RECEIVED_MY_CHANNEL_MEMBERS: null,