[TASK] Modernize EM FileHandlingUtility

The extension manager `@internal` class `FileHandlingUtility`
has a circular dependency to `InstallUtility`: Both inject
each other.

The patch resolves this by implementing
`reloadPackageInformation()` in `FileHandlingUtility` on
its own.

The class is modernized along the way with more type
hints, constructor property promotion, having all
public methods on top, and a unit test cleanup.

Resolves: #101641
Releases: main
Change-Id: I86061da7c92ad00c7c7df89d6b31a9b3ec03e9a0
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/80495


Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Stefan B�rk <stefan@buerk.tech>
Reviewed-by: Stefan B�rk <stefan@buerk.tech>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>