[BUGFIX] Use strict flag in signalslot dispatcher

To avoid exceptions with complex structures, the strict flag
must be used in the in_array check.

Resolves: #82736
Releases: master, 8.7, 7.6
Change-Id: I3ecf859e3e3cc70ab40b10ef9052d46e8b486957
Reviewed-on: https://review.typo3.org/55189


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>