Do not throw error if app manifest is not yet loaded

src/views/app.js

@@ -164,6 +164,8 @@ angular.module('Application').controller('AppController', ['$scope', '$location'
     };
 
     $scope.isProxyApp = function (app) {
+        if (!app || !app.manifest) return false;
+
         return app.manifest.id === 'io.cloudron.builtin.appproxy';
     };