This commit adds a test in order to strengthen the behaviour of recurring subtasks. This test asserts that child with depth > 3 are not copied in a recurrence, that recurrent subtask are well copied with the recurrence correctly set. This commit prepares the recurrence refactoring. task-2660756 closes odoo/odoo#77632 Signed-off-by: LTU-Odoo <IT-Ideas@users.noreply.github.com>