[TASK] Validate models on clientside

Resolves: #58647
Releases: 6.2

Change-Id: Ieafeb8e19f62c7687b4209c9216e7a270f2fc372
Reviewed-on: https://review.typo3.org/29958
Reviewed-by: Nico de Haen
Tested-by: Nico de Haen