[DOCS] Fix outdated TypoScript sample

Use new Symfony TypoScript condition syntax instead
of outdated syntax.

Releases: main,11.5,10.4
Resolves: #97847
Change-Id: Ib0711c2ed871762415b022159a3c6c4b5e688a10
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/75054


Tested-by: core-ci <typo3@b13.com>
Tested-by: Björn Jacob <bjoern.jacob@tritum.de>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Björn Jacob <bjoern.jacob@tritum.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Benni Mack <benni@typo3.org>