[BUGFIX] Deprecation free \ArrayAccess in ArrayAccessClass

Set #[\ReturnTypeWillChange] and corresponding @todo comments to
methods of implemented interfaces in ext:extbase ArrayAccessClass
to avoid deprecation messages without breaking compatibility.

Resolves: #95752
Releases: master
Change-Id: I6e3dafd39813e5aa2622dbf3c145aefd3cf4e961
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/71955


Tested-by: core-ci <typo3@b13.com>
Tested-by: Jochen <rothjochen@gmail.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Jochen <rothjochen@gmail.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>