[TASK] Skip disabled tabs for keyboard users

Add tabindex of -1 to disabled tab links to remove them from the tab
keyboard navigation

Resolves: #91701
Releases: master
Change-Id: Ib8488831b169fb61b8e3a131467cd0cca7666e9a
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/66321


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>