Update PAM auth missing

[jemrobinson]

✅ Checklist

• I have searched open and closed issues for duplicates.
• This is a problem observed when deploying a Data Safe Haven.
• I can reproduce this with the latest version.
• I have read through the documentation.
• This isn't an open-ended question (open a discussion if it is).

💻 System information

• Operating System: macOS
• Data Safe Haven version: release-v5.0.0 @ f2266e6

📦 Packages

List of packages

Paste list of packages here

🚫 Describe the problem

The Update PAM Auth handler is called by ansible, but this was removed as part of #2108. Either this handler should be restored or the notify call should be removed.

🌳 Log messages

Relevant log messages

workspace-01 python3[33306]: ansible-community.general.pamd Invoked with name=common-session type=session control=optional module_path=pam_systemd.so new_type=session new_control=optional new_module_path=pam_mkhomedir.so module_arguments=['skel=/etc/skel umask=0022'] state=after path=/etc/pam.d backup=False
workspace-01 desired_state.sh[5047]: ERROR! The requested handler 'Update PAM auth' was not found in either the main handlers list nor in the listening handlers list

♻️ To reproduce

Attempt to deploy an SRE from this branch.

[jemrobinson]

Closed by #2122