When people (un)subscribe from mail channels through frontend interface
a confirmation email is sent. However if this emails fails if may be
displayed in channel chatter as there is an underlying ``mail.message``.
As this message contains recipient-specific content it is better to avoid
displaying it.
Mail message_type is therefore set to ``user_notification`` meaning only
author and recipient have access to message content. Moreover it is never
displayed in any chatter.
In this commit we also remove custom layouting of mail template bodies. We
instead fall back on rendering template body encapsulated within a notification
layout.
Finally some more information for author is also added: author is set to
channel creator, and email_from to formatted email of the company instead
of its simple version.
LINKS
Task ID-2070632 (main task)
Task ID-2419762 (followup task)
COM PR odoo/odoo#62859
ENT PR odoo/enterprise#15172
UPG PR odoo/upgrade#2005
Thibault Delavallée
31abe454b9