nsd: Update to 4.6.1

CHangelog:
4.6.1
================
FEATURES:
- Set ALPN "dot" token during connection establishment as per RFC9103
  section 7.1 (Thanks Cesar Kuroiwa).
- Add SVCB dohpath support
BUG FIXES:
- Fix static analyzer reports, fix wrong log print when skipping xfr,
  fix to print error on pipe read fail, and assert an xfr is in
  progress during packet checks.
- Use AC_PROG_CC_STDC with autoconf versions prior to 2.70.
- Add missing documentation for zone verification.
- Fix #212: Change commandline control actions to always log.
- Merge #231 from moritzbuhl: Fix checking if nonblocking sockets work
  on OpenBSD.
- Change zone parsing to accept non-trailing newline.

(ryoon)