Also includes these related changes:
* Export `oldContainer` and `newContainer` among the `customize-preview-menu-refreshed` event params for themes to be able to more easily re-initialize the DOM elements.
* Improve performance for partial refresh by only sending settings related to the menu being previewed.
* Fix previewing of menu assigned to Custom Menu by exporting a menu `term_id` as opposed to an object, as the former is more stable for comparing in in args hashes.
* Do full refresh of preview when nav menu unassigned so that the layout can be updated.
* Harden conditions for when partial refresh is eligible for a `wp_nav_menu()` instance.
Fixes#32841.
git-svn-id: https://develop.svn.wordpress.org/trunk@33138 602fd350-edb4-49c9-b593-d223f7449a82
2a8973f117