[BUGFIX] Accept native TIME value '00:00:00' in backend forms

Native date/time types have a zero-value, which is '0000-00-00 00:00:00'
for DATETIME and '00:00:00' for TIME. For DATETIME values this position
in time is really special - however, for TIME values '00:00:00' it would
refer to midnight, which actually is common use case (and currently not
possible in backend forms).

Resolves: #97216
Releases: main, 11.5
Change-Id: Id77a3485e86008ff7c39319679120b2a73b0386c
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/74153


Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Oliver Bartsch <bo@cedev.de>