Optional customer profile, used to meet Travel Rule / AML obligations.
profileId is returned as Subscription.customerProfileId; the rest
of the profile is write-only and never returned by the API.
EU merchants: merchants operating under the EU regulatory workflow
must supply a complete customer profile with every subscription, to meet
Travel Rule / AML obligations. The profile must be an individual (with
firstName, lastName, dateOfBirth, and a full address —
streetAddress, city, postalCode, country) or a company (with
registeredName, registrationNumber, and a full address); a
reference profile is not accepted. A missing or incomplete profile is
rejected with HTTP 422 and error code CUSTOMER_PROFILE_REQUIRED. For
other merchants the profile remains optional.