[TASK] Remove obsolete htmlarea display hotfix

The display hotfix for the old RTE was required to bypass some
initialization issues. This hotfix is not required anymore and improves
the collapse and scroll performance when having a lot of collapsed
panels in the record list, e.g. if EXT:static_info_tables is installed.

Resolves: #81051
Releases: master
Change-Id: I9acd88402ea998be95b1fdb531f535d2f4edb258
Reviewed-on: https://review.typo3.org/52643


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>