[BUGFIX] Fix handling of ClosureFinisher

Check if the incoming optionValue is a closure and return early in such
case.

Resolves: #82550
Releases: master, 8.7
Change-Id: I0f6b12b8ed777906bfe7bc6849841b246e95bbd3
Reviewed-on: https://review.typo3.org/54213


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Ralf Zimmermann <ralf.zimmermann@tritum.de>
Reviewed-by: Bjoern Jacob <bjoern.jacob@tritum.de>
Reviewed-by: Joerg Boesche <typo3@joergboesche.de>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Bjoern Jacob <bjoern.jacob@tritum.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Andreas Fernandez <typo3@scripting-base.de>
Tested-by: Andreas Fernandez <typo3@scripting-base.de>