[BUGFIX] Fix UserRepository instantiation in UserUtility::getCurrentUser()

[smirgol]

When using makeInstance() to get the UserRepository in getCurrentUser(), the inject methods (like injectPersistenceManager) might not get called under certain circumstances in TYPO3 v13.

This can cause "Typed property Repository::$persistenceManager must not be accessed before initialization" errors when the repository is used.

Changed to use container->get() instead of makeInstance() which ensures proper dependency injection.

Tested with TYPO3 v13.4.