[FIX] l10n_in_purchase: right journal id in bills

The journal id from a purchase order was not
taken into account when creating the bill

Override _prepare_invoice method and add
the journal_id to the vals.

opw-3080805

closes odoo/odoo#107790

X-original-commit: ce2b0f8d
Signed-off-by: Brice Bartoletti (bib) <bib@odoo.com>
Signed-off-by: Guillaume Vanleynseele (guva) <guva@odoo.com>

addons/l10n_in_purchase/models/purchase_order.py

@@ -41,3 +41,9 @@ class PurchaseOrder(models.Model):
                 if not l10n_in_gst_treatment:
                     l10n_in_gst_treatment = order.partner_id.vat and 'regular' or 'consumer'
                 order.l10n_in_gst_treatment = l10n_in_gst_treatment
+
+    def _prepare_invoice(self):
+        invoice_vals = super()._prepare_invoice()
+        if self.l10n_in_journal_id:
+            invoice_vals.update({'journal_id': self.l10n_in_journal_id.id})
+        return invoice_vals