[IMP] sale: creating an invoice from a sale order now triggers _onchange_partner_id

We need to trigger _onchange_partner_id manually in order to allow computations related to the partner change and to avoid creating bridge modules.

addons/sale/models/sale.py

@@ -538,6 +538,8 @@ class SaleOrder(models.Model):
             # Necessary to force computation of taxes. In account_invoice, they are triggered
             # by onchanges, which are not triggered when doing a create.
             invoice.compute_taxes()
+            # Idem for partner
+            invoice._onchange_partner_id()
             invoice.message_post_with_view('mail.message_origin_link',
                 values={'self': invoice, 'origin': references[invoice]},
                 subtype_id=self.env.ref('mail.mt_note').id)