[TASK] Remove unused labels related to the old page tree

Resolves: #103089
Releases: main
Change-Id: I87cfaf2baeafb290930cb6142e80ad490fb1a05c
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/82872


Reviewed-by: Benjamin Kott <benjamin.kott@outlook.com>
Tested-by: Benjamin Franzke <ben@bnf.dev>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Benjamin Kott <benjamin.kott@outlook.com>
Reviewed-by: Benjamin Franzke <ben@bnf.dev>