Confirms a user's registration. The request body will contain the verificationId. You may also be required to send a one-time use code based upon your configuration. When the application is configured to gate a user until their registration is verified, this procedures requires two values instead of one. The verificationId is a high entropy value and the one-time use code is a low entropy value that is easily entered in a user interactive form. The two values together are able to confirm a user's registration and mark the user's registration as verified.