chore(tests): Fix typings tests

Author: davideast

test/typings-test/index.ts

@@ -1,9 +0,0 @@
-/**
- * This file just imports from a path that was previously known to having
- * typings errors because it relied on an ambient namespace for firebase,
- * which wouldn't necessarily have been loaded.
- */
-
-import {FirebaseSdkAuthBackend} from 'angularfire2/auth/firebase_sdk_auth_backend';
-
-const Backend = FirebaseSdkAuthBackend;