[BUGFIX] getPageOverlayHook has to use GeneralUtility::getUserObj

The introduction of getPagesOverlay in
commit f6f12f0fcfef0b565a4fcb9f31dd6e780c828ed
modified the hook to use GeneralUtility::makeInstance instead of
GeneralUtility::getUserObj which is a breaking change.

We revert this change now, and use GeneralUtility::getUserObj again.

Change-Id: I43521b85308a69cdafb8fbc5a374d2b99dc22875
Resolves: #66557
Related: #64258
Releases: master
Reviewed-on: http://review.typo3.org/38876


Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Markus Klein <klein.t3@reelworx.at>
Tested-by: Markus Klein <klein.t3@reelworx.at>