Context:

Next to serialised object variables, the engine also seems supports native json variables: https://docs.camunda.org/manual/latest/user-guide/data-formats/json/#native-json-variable-value 

We should evaluate whether we can support this type of variable with the same logic that we are implementing for object variables with OPT-1641.

AT:

• evaluate whether the flattening and raw import of object variables serialised as JSON can also be applied to plain JSON variables
• If possible, implement and document this