[FIX] project: recurrent task layout

The main goal of this commit, is to add missing `colspan="2"`.
We also hide the div and its label at the same time.

Steps to reproduce:
* Open Project
* Select a project
* Select a task
* Click on Recurrent checkbox (if not checked)
* Select the Recurrent Notebook => BUG

closes odoo/odoo#102394

Signed-off-by: Adrien Dieudonné (adr) <adr@odoo.com>