Sometimes the URL prefix switches from a http to a https, this patch harden the
code that removes the URL prefix from wikidata Q-name, issue has been reported
in [1].
[1] https://github.com/searxng/searxng/pull/3437#issuecomment-2082121730
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>