[BUGFIX] Fix formEngine SelectCheckBox word-wrap on small screens

This patch enables word-wrap in a form element `type=select`
with `renderType=selectCheckBox` on small screen devices like
tablet portrait. It prevents the list from sticking out of the right
viewport border.

Only the case when TYPO3_CONF_VARS/BE/debug = false was
taken into account.

Resolves: #86391
Releases: master
Change-Id: Ia894b0a7481feb7a083bc583ff037063093f4e9c
Reviewed-on: https://review.typo3.org/58400


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Georg Tiefenbrunn <georg.tiefenbrunn@gmail.com>
Tested-by: Georg Tiefenbrunn <georg.tiefenbrunn@gmail.com>
Reviewed-by: Michael Oehlhof <typo3@oehlhof.de>
Reviewed-by: Frank Naegler <frank.naegler@typo3.org>
Tested-by: Frank Naegler <frank.naegler@typo3.org>