[BUGFIX] Harden RootlineUtility::enrichWithRelationFields

In some rare cases (e.g., for some Console commands),
RootlineUtility::enrichWithRelationFields might be run without
any TCA, which leads to a crash. This is now avoided.

Resolves: #93949
Releases: master, 10.4
Change-Id: I7725b99341f55aa20279abccb35a79e4fb574409
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/68802


Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Oliver Bartsch <bo@cedev.de>