[TASK] Use PHP class name resolution over strings

Some TCA configurations were still using strings for
class references in the itemsProcFunc option.

Since this is error-prone and also prevents proper IDE
support, all remaining places are changed to use the
automatic PHP class name resolution with ::class.

Resolves: #93753
Releases: master
Change-Id: I853492ae7f590171d7a3e8e422f40728f7e879b1
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/68466


Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: core-ci <typo3@b13.com>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>