static validateRoles (roles) {
    for (const r of roles) {
      if (!systemRolesMapping[r] && !r.startsWith('role:')) {
        return false;
      }
    }

    return true;
  }
Determines whether the roles are valid.
Valid roles are system roles or roles that start with 'role:'
@returns {boolean} true if the roles are valid, false otherwise.