dns/unbound: update to 1.23.1
Release Notes: https://nlnetlabs.nl/news/2025/Jul/16/unbound-1.23.1-released/
PR: 288276
Reported by: Jaap Akkerhuis <jaap@NLnetLabs.nl> (maintainer)
MFH: 2025Q3
Security: e27ee4fc-cdc9-45a1-8242-09898cdbdc91
(cherry picked from commit 9a2fad7839ef40dd0e12b9c9e45654239c1de736)