dns/nsd: Security update 4.15.2 => 4.15.3

Release Notes:
https://community.nlnetlabs.nl/t/nsd-4-15-3-security-release/3490

PR: 299412
Approved by: osa, vvd (Mentors, implicit)
Security: CVE-2026-101337
Security: CVE-2026-101338
Security: CVE-2026-101339
Security: CVE-2026-101341
MFH: 2026Q4