[FIX] account: check entry at posting

External addons (such as the POS) can create entries and end up
bypassing the `_check_balanced` in the whole process.

We force a check at posting, since at this point there is no reason to
have an unbalanced entry anymore.

opw-2168096

closes odoo/odoo#49489

X-original-commit: 88902e2d3953a311dfb3629daeebf22b8874b6e9
Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>

addons/account/models/account_move.py

@@ -2307,6 +2307,10 @@ class AccountMove(models.Model):
             lambda m: m.is_invoice(include_receipts=True) and m.currency_id.is_zero(m.amount_total)
         ).action_invoice_paid()
 
+        # Force balance check since nothing prevents another module to create an incorrect entry.
+        # This is performed at the very end to avoid flushing fields before the whole processing.
+        self._check_balanced()
+
     def _auto_compute_invoice_reference(self):
         ''' Hook to be overridden to set custom conditions for auto-computed invoice references.
             :return True if the move should get a auto-computed reference else False