[BUGFIX] TCA maxitems for FAL permissions wrong

The setting for maxitems in the TCA of be_users and be_groups for
FAL permissions are wrong.
Fix the value to match the number of available options.

Resolves: #59263
Releases: 6.2
Change-Id: Ib38aab8bbd1f5fe9287ff0523139f88520f27e37
Reviewed-on: https://review.typo3.org/30518
Reviewed-by: Frans Saris
Reviewed-by: Alexander Opitz
Tested-by: Alexander Opitz
Reviewed-by: Helmut Hummel
Tested-by: Helmut Hummel