[Accessible Slick] Thumbnail navigation no longer navigate slides

Problem/Motivation

Thumbnail navigation no longer navigate slides when thumbnail navigation clicked.

Breaking changes:

• Aside from #3220286: [Accessible Slick] Provide a check for breaking changes with Accessible Slick → ,
• it appears to be a conscious decision to not support thumbnail navigation mentioned here,
• and also the removal of focusOnSelect option which triggers advancing slides here.

Steps to reproduce

1. Create thumbnail navigation aka asNavFor.
2. Slides should move when clicking thumbnails, but not.

Proposed resolution

No available solution for now without extra legs.
Even at https://accessible360.github.io/accessible-slick/ as of this writing, the thumbnail navigation does nothing. Meaning the thumbnail navigation is no longer navigating slides.

Hopefully this is just an overlook.

However we can also prepare to reserve original behavior with focusOnSelect for future fix.

Remaining tasks

Write a patch, review.

User interface changes

None.

API changes

None.

Data model changes

None.