[BUGFIX] Use correct language constraint in PageLayoutController

When calculating the number of hidden elements for the
currently displayed language columns in the page module,
the corresponding language constraint is now properly set.

Considering more then one language is now only done,
in case language mode with a language > 0 is selected.

Additionally, L=-1 is now properly taken into account.

Some further cleanup of the method is done. The actually
defined field names of corresponding enable columns are
now used instead of the static ones.

Resolves: #99720
Releases: main, 11.5
Change-Id: I751ea0d2f2de88d5eb208215bb81543fc01ca32b
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/77617


Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Fabien Udriot <fudriot@omic.ch>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Oliver Bartsch <bo@cedev.de>