Deserialisation of embedded optional type hinted sum types

[nolledge]

Given this sum type with a type hint field, optionally embedded in a test class:

  @JSONTypeHintField
  sealed abstract class TypeHintEnum
  case object Varialtion1 extends TypeHintEnum
  case object Varialtion2 extends TypeHintEnum

  object TypeHintEnum {
    implicit val json: JSON[TypeHintEnum] = deriveJSON[TypeHintEnum]
  }

  case class Test5(name: String, @JSONEmbedded embedded: Option[TypeHintEnum])
  object Test5 {
    implicit val json: JSON[Test5] = jsonProduct(apply _)
  }

The desieralisation of this json to the test class

"""{ "name": "ze name" }"""

Fails like this:

[info] - should support the absence of optional embedded type hinted attributes *** FAILED *** (24 milliseconds)
[info]   io.sphere.json.JSONException: Missing type field 'type' in '{"name":"ze name"}'
[info]   at io.sphere.json.package$.getFromJValue(package.scala:74)
[info]   at io.sphere.json.package$.getFromJSON(package.scala:60)
[info]   at io.sphere.json.package$.getFromJSON(package.scala:63)

Instead of setting the embedded field to None.

[nolledge]

Added a test here: https://github.com/commercetools/sphere-scala-libs/commit/0ee1f85f4e3c8c464740b36461831012ef97d348 (name: support the absence of optional embedded type hinted attributes)