[BUGFIX] Disable FormEngine's save button on submit

To avoid issues with slow internet connections in combination with the
"Refresh required" modal the save button of the FormEngine is now
disabled on submit.

Resolves: #88637
Releases: master, 9.5
Change-Id: Ib89753350992eb135276cac21995acd81a64f1ae
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/63623


Reviewed-by: Susanne Moog <look@susi.dev>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Christian Eßl <indy.essl@gmail.com>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Christian Eßl <indy.essl@gmail.com>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>