ubuntu-cpc projects do not correctly override openssh-server password-authentication value for debconf

[Thomas Bechtold]

While working on LP:#1968873 , it was mentioned that the passwordauthentication config option from sshd is not correctly set.
Using a sshd_config.d/ snippet instead of directly modifying /etc/ssh/sshd_config does not take into account that the openssh-server package does have a debconf config & template :

$ sudo debconf-show openssh-server
  openssh-server/listenstream-may-fail:
* openssh-server/password-authentication: true
  openssh-server/permit-root-login: true

So instead of using a config snippet, /etc/ssh/sshd_config and the debconf database needs to be modified .

ProblemType: Bug
DistroRelease: Ubuntu 23.10
Package: livecd-rootfs 23.10.49
ProcVersionSignature: Ubuntu 6.5.0-5.5-generic 6.5.0
Uname: Linux 6.5.0-5-generic x86_64
NonfreeKernelModules: zfs
ApportVersion: 2.27.0-0ubuntu3
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: ubuntu:GNOME
Date: Fri Sep 29 13:05:01 2023
InstallationDate: Installed on 2023-05-10 (142 days ago)
InstallationMedia: Ubuntu 23.04 "Lunar Lobster" - Release amd64 (20230418)
ProcEnviron:
 LANG=en_US.UTF-8
 PATH=(custom, no user)
 SHELL=/usr/bin/zsh
 TERM=xterm-256color
 XDG_RUNTIME_DIR=<set>
SourcePackage: livecd-rootfs
UpgradeStatus: Upgraded to mantic on 2023-07-19 (72 days ago)