[BUGFIX] Do not use invalid TSConfig in linkvalidator

To display the linkvalidator error messages for linkhandler link types,
the name of the linked table is read from the TCA instead from page
TSconfig (from a hardcoded page UID 1).

Resolves: #54523
Releases: master, 6.2
Change-Id: I165813a03cd4574c20981e35a9e53cfdeacfc421
Reviewed-on: http://review.typo3.org/33213
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>