[BUGFIX] Catch UnknownLinkHandlerException in InputLinkElement

Catch another exception to avoid a breaking backend.

Resolves: #82850
Releases: master, 8.7
Change-Id: I349aae21932beb5d45c1cec1b1211d3400d1d969
Reviewed-on: https://review.typo3.org/54469


Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>