Prevent angular erros if app is null in some filter

src/js/index.js

@@ -199,18 +199,21 @@ app.filter('installError', function () {
 
 app.filter('activeTask', function () {
     return function (app) {
+        if (!app) return false;
         return app.taskId !== null;
     };
 });
 
 app.filter('installSuccess', function () {
     return function (app) {
+        if (!app) return false;
         return app.installationState === ISTATES.INSTALLED;
     };
 });
 
 app.filter('appIsInstalledAndHealthy', function () {
     return function (app) {
+        if (!app) return false;
         return (app.installationState === ISTATES.INSTALLED && app.health === HSTATES.HEALTHY);
     };
 });