[FIX] mail: avoid copying notified_partner_ids field

The field `notified_partner_ids` has type Many2many with relation table
`mail_message_res_partner_needaction_rel` [1] which is a regular Odoo model
`mail.notification` with some extra fields. One of those fields is required:
`notification_type`.

On copying `mail.message` record, ORM copies Many2many fields directly without
using `default_get` method for `mail.notification` model. Particularly,
`notification_type` get null value and we get an error.

STEPS

1. Create Server Action for `mail.message` model:

```py
for message in (records or record):
    message.copy({
        "subject": message.subject + "(SA copied)",
    })
```

2. Add contextual action
3. Open `mail.message` which has non-empty value on
`notified_partner_ids` (*Partners with Need Action*)
4. Run the Server action via Action menu.

PROBLEM

```
ValueError: <class 'psycopg2.errors.NotNullViolation'>: "null value in column
"notification_type" of relation "mail_notification" violates not-null constraint
DETAIL: Failing row contains (11, 210, null, 3, null, null, null, null, null,
null, null, null, null).
```

SOLUTION

Fix it by adding `copy=False`, because we don't want to copy those values
anyway (confirmed by TDE).

[1]: The relation table is renamed to `mail_notificaiton` in v15+

opw-3069556

closes odoo/odoo#108599

X-original-commit: d68b0f7d6b8f973ddaafdd7526d4f753a1b6abd2
Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>
Signed-off-by: Ivan Elizaryev (iel) <iel@odoo.com>

addons/mail/models/mail_message.py

@@ -135,7 +135,7 @@ class Message(models.Model):
     # mainly usefull for testing
     notified_partner_ids = fields.Many2many(
         'res.partner', 'mail_notification', string='Partners with Need Action',
-        context={'active_test': False}, depends=['notification_ids'])
+        context={'active_test': False}, depends=['notification_ids'], copy=False)
     needaction = fields.Boolean(
         'Need Action', compute='_compute_needaction', search='_search_needaction')
     has_error = fields.Boolean(

addons/test_mail/tests/test_message_post.py

@@ -294,6 +294,10 @@ class TestMessageNotify(TestMessagePostCommon):
         )
         self.assertNotIn(new_notification, self.test_record.message_ids)
 
+        # notified_partner_ids should be empty after copying the message
+        copy = new_notification.copy()
+        self.assertFalse(copy.notified_partner_ids)
+
         admin_mails = [mail for mail in self._mails if self.partner_admin.name in mail.get('email_to')[0]]
         self.assertEqual(len(admin_mails), 1, 'There should be exactly one email sent to admin')
         admin_mail_body = admin_mails[0].get('body')