Ignore Nextstrain citation link for linkcheck

This link has started returning 403 consistently.
<https://github.com/nextstrain/auspice/actions/runs/12242746997/job/34150982036#step:10:24>

docs/conf.py

@@ -79,6 +79,8 @@
      # we have links to localhost for explanatory purposes; obviously
      # they will never work in the linkchecker
      r'^http://localhost:\d+',
+     # This URL will fail and return 403 (broken).
+     r'^https://academic\.oup\.com/bioinformatics/article/34/23/4121/5001388',
 ]
 linkcheck_anchors_ignore_for_url = [
      # Github uses anchor-looking links for highlighting lines but