[BUGFIX] L10nModeUpdater: Cast parentId to integer

To prevent PHP errors in L10nModeUpdater caused by faulty extensions
whose `transOrigPointerField` field is not an integer, the parentId is
now always cast to an int.

Resolves: #79824
Releases: master
Change-Id: I238b89b6fec476731f16807125eb89e9198f50c4
Reviewed-on: https://review.typo3.org/51757


Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>