[FW][FIX] sms: remove sms notifications at uninstall

Currently when uninstalling SMS notifications linked to SMS are kept but set as
email notifications. This makes no sense as they are not linked to any outgoing
mail.mail or email address. As the SMS are removed and as the SMS feature is
not available anymore it is better to simply remove existing SMS notifications.

Task-2778461

closes odoo/odoo#88970

X-original-commit: f307a6c19a2dbe64ba6120a00610063f256102d5
Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>

addons/sms/models/mail_notification.py

@@ -9,7 +9,7 @@ class MailNotification(models.Model):
 
     notification_type = fields.Selection(selection_add=[
         ('sms', 'SMS')
-    ], ondelete={'sms': 'set default'})
+    ], ondelete={'sms': 'cascade'})
     sms_id = fields.Many2one('sms.sms', string='SMS', index='btree_not_null', ondelete='set null')
     sms_number = fields.Char('SMS Number')
     failure_type = fields.Selection(selection_add=[