[TASK] Return early in ContentObjectRenderer::cObjGet()

In case an empty array is passed to ContentObjectRenderer::cObjGet(),
the process returns early, without invoking any array processing and
variable assignments.

Resolves: #100615
Releases: main
Change-Id: I0c21bb02007a5e013861b62437cde40d7cc41fe5
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78659


Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Tymoteusz Motylewski <t.motylewski@gmail.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Oliver Hader <oliver.hader@typo3.org>
Reviewed-by: Oliver Hader <oliver.hader@typo3.org>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Tymoteusz Motylewski <t.motylewski@gmail.com>