Should we check if the json from a service isn't 'None' and show a meaninful message to the user?

In some situations where you can't load the json (for example, behind a firewall), we try to get the contents of the json even if it's `None`.

https://github.com/simplesconsultoria/sc.embedder/blob/3897f9a1f17319d18b64658b75d0a151f79e7fab/src/sc/embedder/content/embedder.py#L334

This way, a cryptic error message is shown to the user. I think we should check if the json is `None` and give more friendly message. What do you think?