[FIX] sale: Translation issue on T&C on Invoices

The sale_note field is translated according to the language of the customer in a SO.
This fix applies the same behavior on the customer invoice.
Inspired from this commit: 978b8f64ec

opw:1830838

addons/sale/models/account_invoice.py

@@ -39,6 +39,9 @@ class AccountInvoice(models.Model):
     def _onchange_delivery_address(self):
         addr = self.partner_id.address_get(['delivery'])
         self.partner_shipping_id = addr and addr.get('delivery')
+        if self.env.context.get('type', 'out_invoice') == 'out_invoice':
+            company = self.company_id or self.env.user.company_id
+            self.comment = company.with_context(lang=self.partner_id.lang).sale_note
 
     @api.multi
     def action_invoice_paid(self):