[TASK] Add RootlineUtility relation tests

Extend the functional RootlineUtilityTest with more
scenarios for resolving category MM, and a "casual"
inline relation.

Resolves: #103680
Releases: main
Change-Id: Ic6e5f9cd604582853431be9415c0fb68b4a41b3c
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/83933


Tested-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Nikita Hovratov <nikita.h@live.de>
Reviewed-by: Nikita Hovratov <nikita.h@live.de>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>