hi,
i have the same problem
i am not sure this might be the answer as in /controllers/front
you can see that code in AddressController.php and in AuthController.php
$this->context->smarty->assign(array(
'one_phone_at_least' => (int)Configuration::get('PS_ONE_PHONE_AT_LEAST'),
'onr_phone_at_least' => (int)Configuration::get('PS_ONE_PHONE_AT_LEAST'), //retro compat
did you find a solution?