[CI] Link-check job failure ignored

[chalin]

Context:

• [ro] Link-check is failing due to missing heading IDs #7940
• https://github.com/open-telemetry/opentelemetry.io/actions/runs/18058636167/job/51391921613

  ro/docs/concepts/glossary/index.html
    hash does not exist --- ro/docs/concepts/glossary/index.html --> /ro/docs/what-is-opentelemetry/#history
    hash does not exist --- ro/docs/concepts/glossary/index.html --> /ro/docs/what-is-opentelemetry/#history
    hash does not exist --- ro/docs/concepts/glossary/index.html --> /ro/docs/what-is-opentelemetry/#history
  ro/docs/demo/telemetry-features/trace-coverage/index.html
  ...
  ro/docs/what-is-opentelemetry/index.html
    hash does not exist --- ro/docs/what-is-opentelemetry/index.html --> #what-next
    target does not exist --- ro/docs/what-is-opentelemetry/index.html --> /ecosistem/registry
  ...
  ========================================================================
  ✘✘✘ failed in 2m27.542776465s
  5 errors in 3575 documents
  make: *** [Makefile:45: check-links-only] Error 1
  cp tmp/.htmltest/refcache.json static/
  npm run _prettier:any -- --write static/refcache.json