[FIX] project, rating: use rating last update to compute satisfaction percentage

The function _compute_parent_rating_percentage_satisfaction used the creation
date of the rating to compute the percentage.
However when a client give a new rating, it updates the old one.
As a result it doesn't give the recent satisfaction percentage,
but the satisfaction percentage of recently created tickets.
In other words recently angry clients from old projects would not appear.

Similarly this method is somewhat reimplemented directly in SQL in the rating
route, which happens to be in the project controller.

opw 1921486

closes odoo/odoo#30752