ensure context exists for JSONDecoder within extension method

Signed-off-by: Matt Bruce <matt.bruce@verizon.com>

MVMCore/MVMCore/Models/Extensions/Decoder.swift

@@ -28,6 +28,9 @@ extension Data {
 extension JSONDecoder {
     /// Decodes a top-level value of the given type from the given JSON representation, and adds the delegate object if provided.
     func decode<T>(_ type: T.Type, from data: Data, delegateObject: DelegateObject?) throws -> T where T : Decodable {
+        if context == nil {
+            add(value: DecodingContext(), for: .contextKey)
+        }
         if let delegateObject = delegateObject {
             add(value: delegateObject, for: .delegateObjectKey)
         }