[TASK] Remove 'validationGroups' in Extbase validators

The concept of 'validation groups' was introduced
with a backport of Extbase validators from Flow back
in 2013. It has never been fully implemented and is
essentially dead code. The patch removes this artifact
from the codebase.

Change-Id: I07f24e20b59992537237433a9268849b2df986d2
Resolves: #96991
Releases: main
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/73643


Tested-by: core-ci <typo3@b13.com>
Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>