[PLT-6800] Clear center and rhs view on other window when leaving a channel (#6723)

* clear center and rhs view on other window when leaving a channel

* move redirection to websocket actions

* close sidebar at websocket action

webapp/actions/websocket_actions.jsx

@@ -341,6 +341,11 @@ function handleUserRemovedEvent(msg) {
             $('#removed_from_channel').modal('show');
         }
 
+        GlobalActions.toggleSideBarAction(false);
+
+        const townsquare = ChannelStore.getByName('town-square');
+        browserHistory.push(TeamStore.getCurrentTeamRelativeUrl() + '/channels/' + townsquare.name);
+
         dispatch({
             type: ChannelTypes.LEAVE_CHANNEL,
             data: {id: msg.data.channel_id, user_id: msg.broadcast.user_id}