[TASK] Remove setting style for broken links in RteHtmlParser

This is a followup for issue #84987. The style that is now set by
CSS file in rte_ckeditor should no longer be set by a PHP method.

Resolves: #85007
Related: #84987
Releases: master
Change-Id: Ie05ed7153802e6a655b3e6e473129a92db613714
Reviewed-on: https://review.typo3.org/56966


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Daniel Goerz <ervaude@gmail.com>
Tested-by: Daniel Goerz <ervaude@gmail.com>
Reviewed-by: Benjamin Kott <benjamin.kott@outlook.com>
Tested-by: Benjamin Kott <benjamin.kott@outlook.com>