[BUGFIX] Fix undefined key warning in ContentObjectRenderer

Resolves: #95993
Releases: master
Change-Id: I8eb6e779ae1d0f02bf8ef0fe3fb5dd02b751cb47
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/72190


Tested-by: Nikita Hovratov <nikita.h@live.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Nikita Hovratov <nikita.h@live.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Oliver Bartsch <bo@cedev.de>