[BUGFIX] Catch error due to invalid record in Linkvalidator scheduler task

Resolves: #82103
Releases: master, 8.7, 7.6
Change-Id: I3e04559c05381c49ab390dc3ad0d3eebddc5a57f
Reviewed-on: https://review.typo3.org/53707


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Joerg Boesche <typo3@joergboesche.de>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Frank Naegler <frank.naegler@typo3.org>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>