Changes to Get event

the response property target/data/oneOf[#/components/schemas/MessageResponse]/author became nullable for the status 200

added the new call_parked enum value to the type response property for the response status 200

added the optional property conversation/_links/related/linked_conversations to the response with the 200 status

added the optional property conversation/_links/related/original_conversation to the response with the 200 status

added the optional property target/data/oneOf[#/components/schemas/MessageResponse]/metadata/rfc5322_message_id to the response with the 200 status

added the required property conversation/is_closed to the response with the 200 status