[TASK] Unify link fields bottom information styling

The LinkElement does now use the same styling
as the SlugElement for the link bottom information.

In case of the LinkElement, this is the "link
explanation", while the SlugElement displays
the regenerated link.

Resolves: #102650
Releases: main
Change-Id: I1a5e68b6a515a0101fa54b70349043328cc1e05e
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/82167


Tested-by: Garvin Hicking <gh@faktor-e.de>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Garvin Hicking <gh@faktor-e.de>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: core-ci <typo3@b13.com>