Safer defaults in an error event for tunnels, fix the details screen when starting

lib/screens/SiteDetailScreen.dart

@@ -53,10 +53,10 @@ class _SiteDetailScreenState extends State<SiteDetailScreen> {
       if (lastState != site.connected) {
         //TODO: connected is set before the nebula object exists leading to a crash race, waiting for "Connected" status is a gross hack but keeps it alive
         if (site.status == 'Connected') {
-          lastState = site.connected;
+          lastState = true;
           _listHostmap();
         } else {
-          lastState = site.connected;
+          lastState = false;
           activeHosts = null;
           pendingHosts = null;
         }

lib/screens/SiteTunnelsScreen.dart

@@ -30,7 +30,7 @@ class _SiteTunnelsScreenState extends State<SiteTunnelsScreen> {
   @override
   void initState() {
     site = widget.site;
-    tunnels = widget.tunnels;
+    tunnels = widget.tunnels ?? [];
     _sortTunnels();
     super.initState();
   }