[TASK] Deprecate $ref param types of method callUserFunction

Passing a non object variable or non null value as third argument
"$ref" into method GeneralUtility::callUserFunction has been
deprecated.

As of TYPO3 version 11.0 said method argument must be either null
or of type object.

Releases: master
Resolves: #90377
Change-Id: I83d75c1c78d1d41d94b6e497b04644e704b902db
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/63075


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Susanne Moog <look@susi.dev>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Susanne Moog <look@susi.dev>