[BUGFIX] Fix PHP 8.0 issues in EXT:setup

Resolves: #94348
Releases: master
Change-Id: Ia8c1f5041057f629ea9dfcc3cde6feba5a1cbe2a
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/69497


Tested-by: core-ci <typo3@b13.com>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Richard Haeser <richard@richardhaeser.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>