[TASK] PHP-functionality instead of GeneralUtility::deHSCentities

Use native PHP-functionality provided by htmlspecialchars()
with a parameter since PHP 5.2.3 to prevent double-encoding
instead of calling deHSCentities().

Change-Id: I2863181259046f16b554770a3f1ed8b03112fedf
Resolves: #50449
Releases: 6.2
Reviewed-on: https://review.typo3.org/22580
Reviewed-by: Markus Klein
Tested-by: Markus Klein
Reviewed-by: Alexander Opitz
Tested-by: Alexander Opitz
Reviewed-by: Pascal Dürsteler
Reviewed-by: Stefan Froemken
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring