[TASK] Convert FluidTemplateContentObjectTest to functional tests

Resolves: #98724
Resolves: #98728
Releases: main
Change-Id: Id046c240ae4e9d3017dc4b8503e23fd8a6a9b4b8
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/76258


Tested-by: core-ci <typo3@b13.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Nikita Hovratov <nikita.h@live.de>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Nikita Hovratov <nikita.h@live.de>