Allows to exclude specific *Task* and all *Timesheets* tracked towards it from
Sale Order.

This feature proves itself useful for *By Employee* billing approach, when
any timesheet entry tracked towards a specific task need to be excluded
from the Sale Order.

This functionality is not available in Odoo, reported in `odoo/odoo#31042 <https://github.com/odoo/odoo/pull/31042>`_.
