Customize: Ensure autofocus deep-linking applies for dynamically-created...

Customize: Ensure autofocus deep-linking applies for dynamically-created panels, sections, and controls.

Removes overly-zealous filtering of autofocus panels, sections, and controls which are unrecognized or for which the user doesn't have the capability to focus (in which case it would no-op anyway). Also defers autofocus logic until instances are created, even after initial `ready` event. This ensures that autofocus can apply for any panels, sections, or controls that get created via the loaded preview.

See #28650.
Fixes #36018.

Built from https://develop.svn.wordpress.org/trunk@36796


git-svn-id: https://core.svn.wordpress.org/trunk@36763 1a063a9b-81f0-0310-95a4-ce76da25c4cd