[FIX]-partner_slow_payer: fix the slow payer method just for out invoice
[FIX]-partner_slow_payer: fix the slow payer method just for out invoice

sysadminmatmoz/odoo-clearcorp,sysadminmatmoz/odoo-clearcorp,sysadminmatmoz/odoo-clearcorp,sysadminmatmoz/odoo-clearcorp