[BUGFIX] Ensure getTreeList() keeps ordering of subpages

Resolves: #96310
Releases: main, 11.5
Change-Id: Ie12ca1683b3d8668deafbd37af03437f047c0ac4
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/72599


Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Benni Mack <benni@typo3.org>