PLT-4430 improve slow channel switching (#4331)

* PLT-4430 improve slow channel switching

* Update client side unit tests

* Convert getChannelsUnread to getMyChannelMembers and address other feedback

* Pull channel members on websocket reconnect

webapp/routes/route_team.jsx

@@ -75,10 +75,11 @@ function preNeedsTeam(nextState, replace, callback) {
         (data) => {
             AppDispatcher.handleServerAction({
                 type: ActionTypes.RECEIVED_CHANNELS,
-                channels: data.channels,
-                members: data.members
+                channels: data
             });
 
+            AsyncClient.getMyChannelMembers();
+
             d1.resolve();
         },
         (err) => {