Verify email of the authorised user

The second step in verifying the authorised user's email. The randomly generated code sent to the authorised user via email, using the authorisedUserEmailVerificationCodeSend operation, is submitted here to verify the authorised user's email.

This is needed as part of the verification process for basic due diligence.

Note that on the Sandbox Environment, the verificationCode is always set to "123456".