fix: start CI when the duplicate check cannot query Jenkins

[mcollina]

ncu-ci run --check-for-duplicates fetches the most recent CI: build linked on the PR to compare its COMMIT_SHA_CHECK. When Jenkins no longer serves that build as JSON (it currently answers with an HTML error page for several node-test-pull-request builds, e.g. 77459), request.json() throws a SyntaxError, the whole run aborts and the Auto Start CI workflow labels the PR request-ci-failed on every attempt. See nodejs/node#65986 (comment).

Catch the failure of that lookup, warn, skip the duplicate check and start a new CI run instead. A matching COMMIT_SHA_CHECK still refuses to start a duplicate.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 58.78%. Comparing base (42e7103) to head (ce74e4a).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1195      +/-   ##
==========================================
+ Coverage   58.74%   58.78%   +0.03%     
==========================================
  Files          53       53              
  Lines       10427    10437      +10     
==========================================
+ Hits         6125     6135      +10     
  Misses       4302     4302              

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