[TASK] Make preperations for backporting Flow validation api

Synced some parts of Extbase validation with the one of
Flow without changing actual behaviour.

Releases: 6.2
Resolves: #48767
Change-Id: I0801f4faaa2d9e0fea31e51704ff0a30ca2c4ccb
Reviewed-on: https://review.typo3.org/21190
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring