re-add test target

Author: urfeex

external-control-frontend/package.json

@@ -8,6 +8,7 @@
     "build": "ng build --configuration=production",
     "lint": "ng lint",
     "lint:fix": "ng lint --fix",
+    "test": "ng test",
     "generatepath": "generate-manifest-constants ../manifest.yaml"
   },
   "private": true,