Currently, unfollowing a project removes the user from all the tasks he was
following. Conversely, following a project or updating your notification
preferences makes the user a follower of all the tasks of the project without
distinction. These consequences are a bit extreme in case the user misclicked,
or simply decided he no longer wanted to be a follower of every newly created
task.
In this commit, when unfollowing a project should not remove the user from
the followers of all the tasks, and following a project should not add the user
to the followers of all the existing active tasks, neither should updating the
user's notification preferences But if the user explicitly update the user's
notification preferences for the project then its propagated to all the tasks
that the user is currently following.
closesodoo/odoo#67142
Task-id: 2440659
Signed-off-by: Laurent Stukkens (ltu) <ltu@odoo.com>