Add message post with attachment test on record of another company than the
user company but for which the user has readonly access on. The goal is to
justify the sudo added in mail_thread:
- in '_message_post_process_attachments' method to create attachment linked
to the record (the creation of attachment linked to a record verify the
right to write to the record, so in readonly we need a sudo);
- in '_message_set_main_attachment_id' method to link the main attachment to
the record. Here we write directly on the record for which we only have
readonly access, so a sudo is needed. Here the attachment is already linked
to the model and we only "tag" it has main attachment (see odoo/odoo#30659)
Task-3178885 (Mail: fix 'readonly' post support)
X-original-commit: odoo/odoo@8486c7ee05
Part-of: odoo/odoo#114511
Pierre-Yves Dufays
0a527ace82