[TASK] Simplify code in TSFE->getPageAndRootlineWithDomain

Some code related to times without Site handling
is cleaned up and logically arranged.

Resolves: #96919
Releases: main
Change-Id: Id2f61048d9bfdd4f0f397bb3afaa1fb883c1faa0
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/73557


Tested-by: core-ci <typo3@b13.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>