Before this commit, when the user duplicates a project with subtasks the
subtasks are duplicating twice. This is because we now duplicate the
subtasks when a task is duplicated.
This commit fixes this issue to duplicate once the subtasks when the
project is duplicated.
Steps to reproduce:
==================
1) Create a project A
2) Create a task T with a subtask
3) Duplicate the project A
Expected Behaviour:
==================
The duplicated project should have 2 tasks (subtasks included)
Actual Behaviour:
================
The duplicated project has 3 tasks (subtasks included), the subtask is
duplicated twice.
This bug has been found during the development of task-2726465
Related PR: #86997closesodoo/odoo#88264
X-original-commit: dcf780026bfa7d76a58aa766b8d190022818ce45
Signed-off-by: Yannick Tivisse (yti) <yti@odoo.com>