CLONE -Assign Roles page - existing users is only sorted by last name, while potential users is sorted by last name then first name

When assigning roles, the potential uses column is sorted first by last name then by first name, while the existing users only sorts by last name.

This is easily fixed by adding the sort option to the get_role_users like so:

if (!$contextusers = get_role_users($roleid, $context, false, 'u.id, u.firstname, u.lastname, u.email, r.hidden','lastname ASC, firstname ASC'))