Issue: In the project task's chatter message, the demo data was used to
create messages such as comments and stage changes, which included a specified
date but 'Task Created' message has current date instead of its creation date.
Cause: The notification for 'Task created' includes the current date because
it was not generated by demo data. This has led to a conflict with the dates of
other messages that were generated using the demo.
Fix: The 'write' method is called on all 'Task Created' messages,
resetting their data to the 'create_date' of the tasks.
task-3289941
closesodoo/odoo#120636
Signed-off-by: Xavier Bol (xbo) <xbo@odoo.com>