post https://partner-api.getpliant.com/api/cardholders/invite
Invite a new cardholder to Pliant. An invite email to the provided email address will be triggered, and the cardholder needs to register with Pliant using our registration flow. This means the cardholder is able to use Pliant web and mobile apps once fully registered. You will receive a callback once the cardholder is fully registered and can be used.