when the list field is empty, it incorrectly shows a warning

[bbtgnn]

It's a bit hard to fix.
The error is generated from parseJSONSchema function, that validates the json schema using ajv.

It throws an error when the json schema is not valid – which is correct.
But in case of an empty enum it should throw a warning, and not an error, because the editor can handle this scenario.

Due to how errors are currently handled, it's not that straightforward and requires some refactorings.