Note: This endpoint should be called only after selfie and
front-second-id both are over.

It is validating user's selfie against photo from ID (1:1 recognition). Also, this call validates if user already exists
in the system (1:N recognition).

It is highly recommended that before calling this process-face endpoint, one should first finish following endpoints:
add-front-secondId, add-back-secondId (not required in
case of passports), process-secondId and add-selfie in order
to get complete result view based on id verification, face recognition and liveness.