[BUGFIX] EXT:form - editor error on mixed option key types

Let the JavaScript 'Inspector-PropertyGridEditor' deal with mixed
option value types (string / int)

Resolves: #79457
Releases: master
Change-Id: I7e9a377d9a5d6e9f1336c25bc114c974a70b7284
Reviewed-on: https://review.typo3.org/51421


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Susanne Moog <susanne.moog@typo3.org>
Tested-by: Susanne Moog <susanne.moog@typo3.org>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>