[BUGFIX] Convert languageId to integer before passing to getLanguageById

ServerRequestInterface->getQueryParams() returns as string value which
has to be converted to an integer before passing it to
Site->getLanguageById().

Resolves: #84652
Related: #84581
Releases: master
Change-Id: Ibfdb2043aa5f6aee1e7e3cf92d752c7f399ef39b
Reviewed-on: https://review.typo3.org/56599


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Frans Saris <franssaris@gmail.com>
Reviewed-by: Simon Gilli <typo3@gilbertsoft.org>
Tested-by: Simon Gilli <typo3@gilbertsoft.org>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Riccardo De Contardi <erredeco@gmail.com>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>