[BUGFIX] Correctly evaluate LIT:0 in TS conditions

Handle LIT:0 used in TypoScript conditions such that is evaluates
to '0' instead of null.
This makes comparisons for equality working.

Resolves: #84543
Releases: master, 8.7
Change-Id: I5eb16d556098179605646faf696f9defaf6195ac
Reviewed-on: https://review.typo3.org/56464


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Tymoteusz Motylewski <t.motylewski@gmail.com>
Tested-by: Tymoteusz Motylewski <t.motylewski@gmail.com>