[TASK] Avoid TSFE->MP

Based on the new PageInformation object attached to the
Request from #102715, we can get rid of usages of
TSFE->MP property.

The patch does this and streamlines an admin panel class
and the seo CanonicalGenerator class along the way.

Change-Id: I0597fdfe5392128a6ae1932305e21a7d25076e29
Resolves: #102797
Related: #102715
Releases: main
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/82277


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