ptz: Fix wrong minimum setting for face_lost_zoomout_timeout

[norihiro]

Description

The setting face_lost_zoomout_timeout should take 0.0 so that the option will be disabled.

How Has This Been Tested?

Tested on Fedora 39.

General checklist

• [x] The commit is reviewed by yourself.
• [x] The code is tested.
• [x] Document is up to date or not necessary to be changed.
• [x] The commit is compatible with repository's license.

Fix #155.