This change moves the check if a page can be
accessed by a BE_USER and if a page is rendered
in preview, while executing a Frontend Request,
to the PSR-15 "TypoScriptFrontendInitialization"
middleware.

This way, TSFE itself does not need to know / set
any preview mechanism itself, since this is now
handled already during the Frontend Request flow.

For this reason, the "determineId()" method can
now include the logic of "fetch_the_id()",
allowing "fetch_the_id()" (protected) to be
completely removed. It's now much easier to
grasp that "determineId()" actually just
determines the final ID / Page / Rootline incl.
translations based on the given request.

This is a precursor patch to introduce new
PSR-14 events that are better suited in the
request workflow than existing hooks.

Resolves: #97176
Releases: main
Change-Id: I3bc1a8709288f01fe6978982572acba6f53f77b3
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/73905
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Susanne Moog <look@susi.dev>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Susanne Moog <look@susi.dev>
Reviewed-by: Benni Mack <benni@typo3.org>