Handle disabled focused tabs with tab JavaScript plugin (#36169)

Handle disabled focused tabs with tab JavaScript plugin (#36169)

* Handle disabled tabs

* Fix after feedback

* Update js/src/tab.js

Co-authored-by: GeoSot <geo.sotis@gmail.com>
* Update js/src/tab.js

Co-authored-by: GeoSot <geo.sotis@gmail.com>
* Commit suggestions via GitHub broke the thing

* Add some unit tests

* Remove temp doc modification

* Add tests for left arrow

* Add disabled tabs in JavaScript Behavior section

* Compact 4 tests to 2 tests

* Compact 4 tests to 2 tests

* Add 'disabled' attribute for all buttons

* Change the disabled pane position only for the vertical version

* Change ids for the confusing first example in JavaScript behavior

* Use disabled attribute instead of the class for buttons in tabs

Co-authored-by: GeoSot <geo.sotis@gmail.com>