[FIX] phone_validation: add country trigger on sanitize phone computation

If country is updated on a record inheriting from mail.thread.phone
its sanitized number should be computed again. Indeed without this
trigger it is not computed and may lead to inconsistencies between
phone numbers and sanitized number.

Task ID-2528169

closes odoo/odoo#70684

Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>