[FIX] ir_demo.py: Force admin access to load demo data

Only admin users should be able to load demo data, if needed.

This is only possible from the settings dashboard, and thus,
the method could be decorated.

See: c002e2eb37

odoo/addons/base/models/ir_demo.py

@@ -1,5 +1,9 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
 from odoo import models
 from odoo.modules.loading import force_demo
+from odoo.addons.base.models.ir_module import assert_log_admin_access
 
 
 class IrDemo(models.TransientModel):
@@ -7,6 +11,7 @@ class IrDemo(models.TransientModel):
     _name = 'ir.demo'
     _description = 'Demo'
 
+    @assert_log_admin_access
     def install_demo(self):
         force_demo(self.env.cr)
         return {