[FOLLOWUP][BUGFIX] Add missing htmlspecialchars() and cleanup in DebuggerUtility

Add missing htmlspecialchars() calls in
EXT:extbase/Classes/Utility/DebuggerUtility.php and cleanup indents in
collections.

Resolves: #83450
Related: #83356
Releases: master
Change-Id: I85a82b7c88e91173485938e95436bad8677694c6
Reviewed-on: https://review.typo3.org/55242


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Alexander Opitz <opitz.alexander@googlemail.com>
Tested-by: Alexander Opitz <opitz.alexander@googlemail.com>