[FIX] base: on_change_country() on res.company should return an ID

Previously, the return value was sometimes an int and sometimes a browse record.
Was PR #22810. Courtesy of Miquel Raïch (Eficent)

addons/account/models/chart_template.py

@@ -715,7 +715,7 @@ class WizardMultiChartsAccounts(models.TransientModel):
             if company_id:
                 company = self.env['res.company'].browse(company_id)
                 currency_id = company.on_change_country(company.country_id.id)['value']['currency_id']
-                res.update({'currency_id': currency_id.id})
+                res.update({'currency_id': currency_id})
 
         chart_templates = account_chart_template.search([('visible', '=', True)])
         if chart_templates:

odoo/addons/base/res/res_company.py

@@ -258,8 +258,8 @@ class Company(models.Model):
         self.ensure_one()
         currency_id = self._get_user_currency()
         if country_id:
-            currency_id = self.env['res.country'].browse(country_id).currency_id.id
-        return {'value': {'currency_id': currency_id}}
+            currency_id = self.env['res.country'].browse(country_id).currency_id
+        return {'value': {'currency_id': currency_id.id}}
 
     @api.onchange('country_id')
     def _onchange_country_id_wrapper(self):