[BUGFIX] Fix condition for USERDEF2 in procesItemState

Fix a wrong condition in the procesItemState method for MENU handling
for the USERDEF2 itemstate, so it would not be ignored anymore.

Initializing the USERDEF2conf was never done, even if one or more
USERDEF2 item states was found, because the condition was checking
for NULL === TRUE, which will never be TRUE.

Resolves: #77284
Releases: master, 7.6
Change-Id: I16c1d21f03c9aa3565744cae90b7f0cb487ec009
Reviewed-on: https://review.typo3.org/49257


Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>