Without this patch, users without access to reading and editing mass mailing contact records are now unable to change a partner's name or email. They'd recieve an exception such as:
AccessError: Sorry, you are not allowed to access this document. Only users with the following access level are currently allowed to do that:
- Mass Mailing/User
(Document model: mail.mass_mailing.contact)
Restrictive ACLs shouldn't restrict normal user operation nor DB consistency, so using sudo mode now and testing behavior.
* Exclude opt_out.
Now opted-out records will not be counted in the "Mailing lists" smart button
in the partner form.
* Avoid duplicate error.
By indicating the exact `partner_id` and ensuring no contacts associated to it are found, you avoid possible duplication errors when several partners share the same name or email.
