[BUGFIX] Route dispatching: Don't rely on id being an integer

The route dispatcher can't rely on id being an integer, as file list for
example uses string identifier.

It is now checked whether the id is an int instead.

Resolves: #82440
Related: #82406
Releases: master
Change-Id: Idddc8484e0a597fec9d61c509d06f36736990c67
Reviewed-on: https://review.typo3.org/54098


Reviewed-by: Matthias Vogel <typo3@kanti.de>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Markus Hölzle <typo3@markus-hoelzle.de>
Tested-by: Markus Hölzle <typo3@markus-hoelzle.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>