With multi-website, activating a customize option (customize_show view) will
actually duplicate the customize view to make it specific.
By doing so, the duplicated view will have a higher ID than the original, and
the original's siblings customize options.
Before this fix, two issues could be seen:
1. When toggling a customize option, it would appear last in the dropdown
afterward. This is because of the views being sorted by (priority, id)
(if the views have the same priority).
2. When toggling, sometimes the views header would be duplicated. This comes
from the JS code that loop through the returned views and create the DOM
by adding a header when the view inherit_id is different than the previous.
Obviously, as 2 views with the same inherit_id could not be grouped together
now that the specific one has a bigger ID, it will create twice the DOM.
=> Check tests in this commit, they have schemas that will explain it clearly
Note: We don't take priority into account for customize menu view order as it
would create the same problem as (2.)
We could have sorted by (inherit_id, priority, name) to avoid the issue
and give the user possibility to order options in header but it was
decided we dont.
Closes#29347
Romain Derie
e0c67651db