Pretty simple.

always remember to backup your default configs kids
mkdir ~/.backupconfigs
sudo cp /etc/pam.d/system-auth ~/.backupconfigs/pam.d.system-auth

Then edit the system-auth pam file
sudo nano /etc/pam.d/system-auth

and change

-auth      [success=2 default=ignore]  pam_systemd_home.so
auth       [success=1 default=bad]     pam_unix.so          try_first_pass nullok

to

auth       [success=2 default=ignore]  pam_unix.so          try_first_pass nullok
-auth      [success=1 default=ignore]  pam_systemd_home.so

Success?