[FIX] account: Prevent crash when having custom coa

- Create manually an account.payment after having created manually some journals
(without installing a coa).
- Install a module containing a coa and calling try_loading_for_current_company or depending
of other module doing such things.

=> Crash because company.chart_template_id is not set.

-opw: 1921711

closes odoo/odoo#30117

addons/account/models/chart_template.py

@@ -142,8 +142,9 @@ class AccountChartTemplate(models.Model):
                 'bank_account_code_prefix': self.bank_account_code_prefix,
                 'cash_account_code_prefix': self.cash_account_code_prefix,
             })
-            wizard.onchange_chart_template_id()
-            wizard.execute()
+            if not wizard.existing_accounting(company):
+                wizard.onchange_chart_template_id()
+                wizard.execute()
 
     @api.multi
     def open_select_template_wizard(self):