[IMP] mail: do not remove cancelled email during the sending

Purpose
=======
It's not the role of the sending method to remove non outgoing emails.

Task-2587345

Part-of: odoo/odoo#73271

addons/mail/models/mail_mail.py

@@ -376,8 +376,6 @@ class MailMail(models.Model):
             try:
                 mail = self.browse(mail_id)
                 if mail.state != 'outgoing':
-                    if mail.state != 'exception' and mail.auto_delete:
-                        mail.sudo().unlink()
                     continue
 
                 # remove attachments if user send the link with the access_token

addons/test_mass_mailing/tests/test_performance.py

@@ -92,3 +92,6 @@ class TestMassMailBlPerformance(TestMassMailPerformanceBase):
 
         self.assertEqual(mailing.sent, 50)
         self.assertEqual(mailing.delivered, 50)
+
+        cancelled_mail_count = self.env['mail.mail'].sudo().search([('mailing_id', '=', mailing.id)])
+        self.assertEqual(len(cancelled_mail_count), 12, 'Should not have auto deleted the blacklisted emails')