[BUGFIX] Use main variables in `HeaderAssets` and `FooterAssets`

Forwards the main template variables to the
`HeaderAssets` and `FooterAssets` sections.

Releases: main, 12.4
Resolves: #100879
Change-Id: I5336eb06b833d98e1605d1cb190b8be0a32c6aa5
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/79031


Reviewed-by: Oliver Hader <oliver.hader@typo3.org>
Tested-by: Oliver Hader <oliver.hader@typo3.org>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: core-ci <typo3@b13.com>