Support deserialization of generic types that are JsonSerializable.

This looks good to handle `List` but nothing more than that. This is good to get us unblocked but we might want to look into more generalized handling in the future for stuff like `Map` or `List>`.

_Originally posted by @alzimmermsft in https://github.com/Azure/azure-sdk-for-java/pull/44208#discussion_r1956573617_