Passed to updateUser by the users routes and the password reset, and sent
by a client to PATCH /api/me, which takes only description and email;
the role and the password change through their own endpoints, and the
username through renameUser, by a moderator only.
optional
password: string
optional
description: string | null
An empty string clears it. Null, like undefined, keeps it.
optional
email: string