Remove duplicate GHSA-jcw8 references

[cookesan]

Removes malformed duplicate dns-sync issue and commit references from GHSA-jcw8-r9xm-32c6 while leaving the clean references intact.

Audit refresh, July 8, 2026:

• Confirmed the advisory still retains the clean upstream issues, fix commit, GHSA, npm advisory, and NVD references.
• Confirmed the GHSA and NVD records for CVE-2017-16100 still resolve.
• Local checks passed: one advisory JSON file changed in the PR diff, JSON parses, git diff --check passes, and the worktree is clean.