[fbjs-scripts] gulp/check-dependencies should handle outdated non-deps safely

[zpao]

This is only an issue after removing dependencies from package.json but we should handle it better. Specifically if you have an outdated package installed npm outdated will report it even if it's no longer a dep. But then out lookup to see if it's ok fails because it expects it.

This is easily handled. We can either skip that package or we can have gulp throw an error saying that you should run npm prune.