Changes to Create an open banking mandate

added the new required request property periodic_limit/per_payment/currency

removed the enum value VISA_A2A of the request property type

changed the pattern of the request property currency from ^[A-Za-z]{3}$ to ^[A-Z]{3}$

removed the optional property created_at from the response with the 201 status

removed the optional property status from the response with the 201 status

added the optional property links to the response with the 201 status