[TASK] Simplify PageRepository code

This change reduces some cognitive load
in some methods to use early returns
instead of nested if statements.

Resolves: #102726
Releases: main
Change-Id: I8093d087f997e07b2d4a97d23ec5f289792b6182
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/82045


Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Oliver Bartsch <bo@cedev.de>