[TASK] Remove superfluous preview renderer

TextPreviewRenderer and TextpicPreviewRenderer
extend the StandardContentPreviewRenderer while
not implementing any custom functionality and
are therefore now removed.

Resolves: #104417
Releases: main
Change-Id: Ia99c3751405f038dbdc57b531650d7657e4a83fc
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/85283


Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Jochen Roth <rothjochen@gmail.com>
Reviewed-by: Jochen Roth <rothjochen@gmail.com>