xfce4-screensaver doesn't honor "loginctl unlock-session"

xfce4-screensaver doesn't honor systemd controlled "loginctl unlock-session" to unlock the screensaver.

Test case:

• Run sleep 15 && loginctl unlock-session in terminal.
• Lock the screen (I think Ctrl+Shift+L by default should be okay).
• Wait for 15 seconds.

Expected result:

The loginctl should unlock the screensaver.

Actual result:

Nothing happens.

This results in requiring to enter the password twice to do user switching when running on Ubuntu 22.04 and using lightdm as the login manager: once for the lightdm and another time to unlock the screensaver.