[DAR-4489][External] Import item-level properties without annotations

[JBWilkie]

Problem

When importing annotations to items in Darwin JSON 2.0, item-level property values are ignored if there are no annotations. This happens because before item-level properties, all properties were tied to annotations, so it made sense to skip import in these cases

However, item-level properties are independent of annotations and so should be able to be imported independently

Solution

Do not skip annotation files for import if they contain item-level properties but no annotations

Changelog

Allow import of item-level properties without annotations

[linear]

DAR-4489 BUG: darwin-py will not import item-level properties unless there is at least one annotation to be imported