Fix normalize error paths

[wuarmin]

Hello 👋,
Thank you for continuing the project!
I have already placed this PR in the old repository and therefore now here, because in my opinion it would still be relevant.

I'm consuming a GraphQL-interface, which returns error-payloads like that:

{
      "data": null,
      "errors": [
        {
          "message": "error",
          "path": null
        }
      ]
}

This caused a NoMethodError: undefined method `each' for nil:NilClass
This PR would fix the behavior.

Thanks
best regards
Armin

[rmosolgo]

Hey, thanks for bringing this over here! I agree this would be a good improvement.