[TASK] Remove outdated t3editor requirejs configuration

With the upgrade to codemirror v6 in #96575 it was forgotten to
remove the RequireJS configuration that is no longer needed, as
codemirror v6 is loaded via ES6 modules and importmap configuration.

Releases: main
Resolves: #98491
Related: #96575
Change-Id: I6fc849ea1ad8bc4f493447f492140617ea6445af
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/75929


Tested-by: Oliver Hader <oliver.hader@typo3.org>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Oliver Hader <oliver.hader@typo3.org>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>