[TASK] Simplify stylesheet and script assignments in ext:form

Avoids round trip through Fluid template, but instead assigns
stylesheets and inline scripts directly via `PageRenderer`.

Resolves: #94969
Releases: master
Change-Id: Ic16c853fc8fcb26204c91b6347616513787fcd78
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/70731


Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>