[FIX] privacy_consent: Avoid permissions error if the user does not have access to privacy.

TT35907

privacy_consent/models/mail_mail.py

@@ -1,4 +1,5 @@
 # Copyright 2018 Tecnativa - Jairo Llopis
+# Copyright 2022 Tecnativa - Víctor Martínez
 # License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
 
 from odoo import models
@@ -21,6 +22,7 @@ class MailMail(models.Model):
                 and not failure_type
             ):
                 res_ids.append(mail.mail_message_id.res_id)
+        if res_ids:
             consents = self.env["privacy.consent"].search([
                 ("id", "in", res_ids),
                 ("state", "=", "draft"),