[FIX] project: Fix wrong recipient display based on email_from

Currently, The customer that is not selected anymore is suggested
as a recipient

steps to reproduce:
1. create a project task without a customer set
2. select a customer, then remove it, then save
3. send a message in the chatter
--> the customer that is not selected anymore is still suggested as
a recipient.
The issue is due to invalid value of partner's email in the field
email_from on task.

So in this commit, when the customer is not defined or is not a child
task then keep the email_From of the task.
(Here we are checking the task.parent_id because when someone update
the email_from on parent it should be updated in child task's
email_from and when we remove the email_From in parent it should not
be removed from child task)

closes odoo/odoo#63042

Taskid: 2339894
Signed-off-by: Yannick Tivisse (yti) <yti@odoo.com>

0 files changed, 0 insertions, 0 deletions