Failure to convert TypeSafeEnum should prevent successful parsing

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Given:

[<Newtonsoft.Json.JsonConverter(typeof<TypeSafeEnumConverter>)>]
type Log = A | B
[<Newtonsoft.Json.JsonConverter(typeof<UnionConverter>, "rule", "Unknown")>] Input =
type DU of = 
    | CaseA of req: Log * res:Log 

the following parses, yielding a Log value of null and NullReferenceException when you touch the res value

"{ "rule": "CaseA", "req": "A" }

this should instead provide a clear parser error

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Resolved by #5