Howdy doesn't work immediately at lock screen on Ubuntu 22.04

There is a delay of about ten seconds before howdy starts detecting my handsome face :).

Linux distribution (if applicable): ubuntu 22.04

Howdy version (`sudo howdy version`): latest

Reproduce the delay at the Ubuntu 22.04 lock screen, then trace Howdy's PAM authentication startup path to determine where detection begins. Done means face detection starts promptly at the lock screen without the reported ten-second delay; the issue names no files or tests to run.

Written by the indexing model from the issue text.