[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: #83356
Releases: master
Change-Id: I03eae07be66bbfb9b5b605359666857e56beba83
Reviewed-on: https://review.typo3.org/55115


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Joerg Boesche <typo3@joergboesche.de>
Reviewed-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>
Tested-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>