Missing support for Structure evaluations

[fabriziodemaria]

Evaluations of complex structure value type, both in Confidence and ConfidenceFeatureProvider, is not supported.

This is particularly confusing in the OpenFeature case, where the API getObjectEvaluation is not working and will always throw at runtime.

[nicklasl]

This is where we go wrong:

confidence-sdk-swift/Sources/Confidence/FlagEvaluation.swift

Line 201 in a4b1e0a

return value.asStructure() as? T

If the evaluation is called using a defaultValue T where T is ConfidenceValue, we return null.
If the evaluation is called using defaultValue = ConfidenceStruct it works.

[fabriziodemaria]

I think it's ok to expect ConfidenceStruct when evaluating a complex schema. So my original message was misleading, saying that evaluations are not supported for Confidence, but it was correct saying that those don't work with the ConfidenceFeatureProvider.

With #193 we made the getObjectEvaluation work, and we also introduced the possibility to use Dictionary as default value in the native Confidence APIs. With that, I think we can close this Issue.

In the future we might want to consider supporting Codable objects in the native Confidence APIs as well, but that is a separate topic