[FIX] mass_mailing: unrestrict qweb rendering for mass mailing users

Mass mailing users need more access rights
for unrestricted qweb expressions

opw-4968616

Author: Florian Vranckx

addons/mass_mailing/models/mailing.py

@@ -50,6 +50,8 @@ class MassMailing(models.Model):
     _rec_name = "subject"
     _systray_view = 'list'
 
+    _unrestricted_rendering = True
+
     @api.model
     def default_get(self, fields_list):
         vals = super(MassMailing, self).default_get(fields_list)