[BUGFIX] Align Storage “is_public” checkbox with checkbox styles

The markup generated by the UserStorageCapabilityService is now
in line with the overall styling of checkboxes in TCA.

Resolves: #83810
Releases: master
Change-Id: I59bb480587bf30e054b855370e33e3d2dbfdfa91
Reviewed-on: https://review.typo3.org/55615


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Riccardo De Contardi <erredeco@gmail.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>