[BUGFIX] Avoid exception of renderType selectCheckBox in workspace

Resolves: #85109
Releases: master, 8.7
Change-Id: I34a269ec2d564a546d4dc2036a97eb1027d2352f
Reviewed-on: https://review.typo3.org/57484


Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Jörg Bösche <typo3@joergboesche.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>