[BUGFIX] Add fallback for array key warnings in DebugUtility.php

Fixed by adding a fallback to the affected array keys.

Resolves: #94863
Releases: master
Change-Id: I373910d106971c101493b0a427d09cf9904ab249
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/70541


Tested-by: core-ci <typo3@b13.com>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Benni Mack <benni@typo3.org>