[BUGFIX] Fix querying form element when clicking "Install" button

Resolves: #88226
Related: #88040
Releases: master
Change-Id: Ie8726b689362119a3d4d087582b3be2cb2b86e4b
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/60572


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Frank Naegler <frank.naegler@typo3.org>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Frank Naegler <frank.naegler@typo3.org>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>