Step to reproduce :
	-set your company country in Italy
	-install accounting
	-install contacts
	-create a new individual contact
	-set the country address of this contact to Italy

Expected Behavior:
No problem

Current behavior:
Error message in function _l10n_it_normalize_codice_fiscale

Explanation:
In this fix commit https://github.com/odoo/odoo/commit/702c01661f255fe9ebbfc04c90b2cd0fa194d1e8


the case where vat is unset but the country is Italy is not rejected
anymore and a unset value is passed in _l10n_it_normalize_codice_fiscale

opw-2822259

closes odoo/odoo#88790

Signed-off-by: Josse Colpaert <jco@odoo.com>