[TASK] Remove option for enabling RTE per user

Because RTE was not always possible in all browsers
in TYPO3 v3.x, a flag to deactivate the RTE
(for Netsacpe users) was added.

Since then, HTMLarea and now CKEditor4 (or with
v12: CKEditor 5) work properly across all
browsers and the setting has no effect anymore,
is therefore removed from the UI.

Resolves: #100634
Releases: main
Change-Id: Iff80f250b2db05394f48ee2b303583cfbf193746
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78681


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>