[IMP] improve visibility changes as per task specification

- Task: https://www.odoo.com/web#id=5183&view_type=form&model=project.task&action=333&active_id=131
- Pad: https://pad.odoo.com/p/r.osgTl7m2AJDF4CQy
I think the formatting of your help is not correct. Using \ in a string you will keep spaces; is it what you intended ? Otherwise juste use "string"\"string"\"string" . Without triple quotes then.