[BUGFIX] Use correct packageManager initializing

As the PackageManager is a singleton class, you should call
GeneralUtility::makeInstance to retrieve the instance. The bootstrap
correctly initializes the first instance and registers it as singleton
already.

Resolves: #85659
Releases: master
Change-Id: I414a3fe4004044b0cdf6d2d8978f7e3463886018
Reviewed-on: https://review.typo3.org/57692


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>