Unhelpful/Misleading Error Message when Credentials File is Empty

[theGOTOguy]

Environment details

• OS: Alpine
• Node.js version: 18.12.0
• npm version: 8.19.2
• @googleapis/google-auth-library-nodejs version: 8.7.0

Steps to reproduce

1. Create an empty gcp_credentials.json file for your gcloud_project with your gcloud_storage_bucket.
2. Use, e.g.:

  const storage = new Storage({
      projectId: gcloud_project,
      keyFilename: 'gcp_credentials.json'
  });

  const bucket = storage.bucket(gcloud_storage_bucket);
  const [metadata] = await bucket.getMetadata();

3. Receive unhelpful error message "TypeError [ERR_INVALID_ARG_TYPE]: The "path" argument must be of type string. Received type boolean (true)"

It would be reasonable to sanity-check the key file and return a more illuminating error message.