Fix pam tests about ansible-collection-hardening HOT 1 OPEN

The reason:

• systemd creates a file /run/nologin, preventing login to the system to users (except for root)
• that file normally is deleted by the systemd service systemd-user-sessions.service (see https://man.archlinux.org/man/systemd-user-sessions.service.8.en). However this service never starts in the failing containers (idk why), thus the file does not get deleted
• this normally does not present a problem since we login into the container as root
• however we check that our pam-config works by simulating a login with pam-tester
• here's the output of the underlying library:

>>> import pam
>>> p = pam.pam()
>>> p.authenticate('testuser', 'root') # -> could not authenticate, although password is correct
False
>>> print(p.code)
7
>>> print(p.reason)
Authentication failure
>>> p.messages
['Password: ', '"System is booting up. Unprivileged users are not permitted to log in yet. Please come back later. For technical details, see pam_nologin(8)."']

• removing the nologin-file is enough to make it work

More info:

• https://access.redhat.com/solutions/6408321
• https://access.redhat.com/discussions/4321031
• https://stackoverflow.com/questions/58682387/error-while-trying-to-ssh-a-docker-container-system-is-booting-up

from ansible-collection-hardening.