[BUGFIX] TreeNode creation and cleanup

Correctly extend and show the children of the
parentnode when a node is added. Clean up
the parent node status when a node is removed
and no longer contains child nodes.

Resolves: #103226
Releases: main
Change-Id: I269380c322cad06902e87406732d8f708c8f9614
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/83158


Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: core-ci <typo3@b13.com>