File: WebAPI/account_authorization_2.proto
Initiating of account level multi-step logon process by client.
Note: Unlike user_session_2.LogonInit used for trader logon, we do not assume that user_name is required for account level logon. Where required, server will request it via AccountLogonRoutineServer.password_requests with password_type=PASSWORD_TYPE_TEXT and user_prompt_type=user_name.