[BUGFIX] Replace usage of deprecated method in ClassSchema

The method getCollectionValueType() is deprecated
since symfony 5.3 and has therefore been replaced
by getCollectionValueTypes().

Resolves: #94435
Releases: master
Change-Id: I05427349f738cb328d547b221ee0224aa04ca57a
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/69658


Tested-by: core-ci <typo3@b13.com>
Tested-by: Jochen <rothjochen@gmail.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Jochen <rothjochen@gmail.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>