[TASK] Remove unused iconRegistry in CheckboxLabeledToggleElement

Constructor is removed as well because it is the same as the parent class.

Resolves: #94755
Releases: master
Change-Id: I918241344f467e84527e295c99b47152bc0f21be
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/70300


Tested-by: core-ci <typo3@b13.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Hader <oliver.hader@typo3.org>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Benni Mack <benni@typo3.org>