We should not default to an empty data, because then it removes the data

https://github.com/Kinto/kinto-wizard/blob/master/kinto_wizard/yaml2kinto.py#L102

We removed the notification config because of that fallback.

Start with kinto_wizard/yaml2kinto.py at line 102 and trace how the empty-data fallback is used when loading YAML into Kinto. Confirm how that fallback removes existing data and how the notification configuration is affected. Done means the fallback no longer removes existing data or causes the notification configuration to be removed.

Written by the indexing model from the issue text.