API handles the calls for starting and authenticating the transaction in one go. The merchant calls this API with the same
parameters as the Transaction Start V16 with the necessary card data appended to it. For existing transactions the orderId
and entranceCode can be passed on instead of the transaction details.

Note: this API will try to process the transaction based upon the settings for the service. This can result in an 3DS challenge,
for which the necessary data will be returned. The payload of the challenge must be sent to the Authorization API.

In case of an SCA Exempted (Low-value-payment) or frictionless transaction the authorization will be handled in this request.