Grav: UserInterface offsetget/offsetexists allow-listed in Twig sandbox let editor-authored content leak hashed_password and 2FA secrets via offsetGet()

Summary system/config/security.yaml's Twig sandbox policy allow-lists offsetget and offsetexists for Grav\Common\User\Interfaces\UserInterface. The concrete Grav\Common\User\DataUser\User class does not filter which fields offsetGet returns, so any sandboxed template with access to a User object...