Customize: Deep-linking to themes section does not work

[westonruter]

As can be seen in #42354, in order to deep-link to a themes section you have to construct a URL like:

/wp-admin/customize.php?autofocus[panel]=themes&autofocus[section]=wporg_themes

It appears there is flaw in the ThemesSection#onChangeExpanded() method whereby it is not expanding its parent panel first.

One should be able to access a given section merely via /wp-admin/customize.php?autofocus[section]=wporg_themes

Introduced in #37661.

[westonruter]

Please review: ​https://github.com/xwp/wordpress-develop/pull/296

[rinkuyadav999]

Yes i notice that it takes a little time to open correct section.

[celloexpressions]

Looks good. As noted on the PR, on small screens, autofocusing to a section doesn't actually show the section contents. That's not critical, but it's a bit odd as it shows the section as checked within the panel, then you need to tap on it. Otherwise, looks ready to merge.

[westonruter]

In 42033:

Customize: Fix deep-linking to sections for themes via autofocus[section] query parameter.

• Expand containing panel when expanding themes section.
• Consolidate UI changes related to a section's expanded state change.
• Prevent collapsing current section when expanding.
• Auto-expand first themes section when expanding panel if one is not expanded already.

See #37661, #42354.
Fixes #42360.