[BUGFIX] Initialize inline form fields just once

Due to a bug, inline form fields were initialized twice, causing
internal application state issues in FormEngine and Modal handling.

Resolves: #96009
Releases: master
Change-Id: I07f75ae90826eec77515ec84e69f4154828295a1
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/72214


Tested-by: core-ci <typo3@b13.com>
Tested-by: Chris Müller <typo3@krue.ml>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Oliver Hader <oliver.hader@typo3.org>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Oliver Hader <oliver.hader@typo3.org>