[FIX] account: call _onchange_price_subtotal on demo data

The demo data created by account did not call _onchange_price_subtotal
on the created account_lines, making the total debit
and credit not matching the state of the lines.

closes odoo/odoo#77771

Related: odoo/enterprise#23738
Signed-off-by: Olivier Colson <oco@odoo.com>

addons/account/demo/account_demo.py

@@ -318,6 +318,7 @@ class AccountChartTemplate(models.Model):
 
             created.line_ids._onchange_product_id()
             created.line_ids._onchange_account_id()
+            created.line_ids._onchange_price_subtotal()
 
             created._recompute_dynamic_lines(
                 recompute_all_taxes=True,