[FEATURE] Add FAL support for FlexFormProcessor

Support for FAL references in FlexForms is added to the
FlexFormProcessor. No additional processing is needed
anymore to resolve FAL references.

Resolves: #94501
Releases: main
Change-Id: If3e3355f1dda497be5d7f498b9df85cb56de96d0
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/69753


Reviewed-by: Göran Bodenschatz <g.bodenschatz@ecentral.de>
Tested-by: Simon Schaufelberger <simonschaufi+typo3@gmail.com>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Simon Schaufelberger <simonschaufi+typo3@gmail.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>