Indicates the type of SCA excemption (e.g. Acquirer TRA or MIT) to be applied.
Please note that Acquirer Exemptions and Merchant Initiated Transactions (MIT) can also be requested by authorization without authentication (i.e. EMV 3DS or EMV 3DS Data Only). Please note that merchantInitiatedTransaction is only valid in combination with credentialOnFile.
At the moment only "lowValue" exemption is supported.