HostKey comment "# Req 20" breaks key based auth

[abtreece]

Describe the bug
Working on implementing Okta Advanced Server Access (formerly ScaleFT) which utilizes client certificate authentication for SSH. Connections are failing with "ssh: handshake failed: open : no such file or directory". After much troubleshooting the problem appears to be the "# Req 20" comment that is added to the HostKey configuration in /etc/ssh/sshd_config

ansible-ssh-hardening/templates/opensshd.conf.j2

Line 35 in 4ee9bf2

HostKey {{key}} # Req 20

Expected behavior
Successful SSH login to the instance.

Actual behavior

$ ssh bastion.<domain.ext>
The authenticity of host <IP> cannot be be established.
ecdsa-sha2-nistp256 key fingerprint is SHA256:wOFz1AOvH479dWUnISYThbz+iIButdnGPz4O/vtOI6s.
Add to known_hosts?: yes
error: ssh: handshake failed: open : no such file or directory
ssh_exchange_identification: Connection closed by remote host

Example Playbook
N/A

OS / Environment
Amazon Linux 1

Ansible Version
2.6.4

Role Version
All

Additional context
Add any other context about the problem here.