[IMP] base: avoid ormcache clear when setting ir.default to the same value

Purpose
=======

On the res.config.settings model for example, calling execute without
having changed a single parameter will make several writes on
ir.default records.

However, even if the written and the current values are the same,
the cache will be invalidated several times.

Part-of: odoo/odoo#82999

odoo/addons/base/models/ir_default.py

@@ -80,7 +80,9 @@ class IrDefault(models.Model):
             ('condition', '=', condition),
         ])
         if default:
-            default.write({'json_value': json_value})
+            # Avoid clearing the cache if nothing changes
+            if default.json_value != json_value:
+                default.write({'json_value': json_value})
         else:
             self.create({
                 'field_id': field.id,