Serialized SwitchNode looses "order and "direction" properties

[MarinPinchinatLoth]

• Do you want to request a feature or report a bug?
  A bug

• What is the current behavior?
  When serialized to Json, SwitchNodes are loosing their 'order" and "direction" properties.

• If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem

1. Create a SwitchNode with an order and a direction.
2. Serialize it using "writeJsonContent" method
3. Deserialize it.

Order and direction are now null values.

• What is the expected behavior?
  Order and direction values should remain the same as before serialization.

• What is the motivation / use case ?
  We need to serialize graphs in order to store them into a database

• Please tell us about your environment:

  • PowSyBl Version: 2.6.0

• Other information (e.g. detailed explanation, stacktraces, related issues, suggestions how to fix, links for us to have context, eg. stackoverflow, spectrum, etc)

Workaround : we created a CustomSwitchNode class extending SwitchNode, overriding writeJsonContent method.