16650 impossible to unpublicize query by other user even when permission is assigned

[``* `#16650` Impossible to unpublicize query by other user even when permission is assigned``](https://www.openproject.org/work_packages/16560)
@ulferts according to [the docs](http://apidock.com/rails/v4.0.2/ActiveModel/Dirty/changed_attributes) ``changed_attributes`` should actually be fine.