[BUGFIX] Check for plain integer values in QueryGenerator::cleanInputVal()

Incoming field values are now also checked for being plain integers to
be able to handle timestamps properly.

Resolves: #89154
Related: #84588
Releases: master, 9.5
Change-Id: I220096faa563b3700eceb8a85839eed2a70d2170
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/61670


Tested-by: Frank Nägler <frank.naegler@typo3.org>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Frank Nägler <frank.naegler@typo3.org>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>