Re-enabling "Lock after screen turns off" locks the screen 1 second after instead of 5 seconds (default value).

## What Happened
By default the screen is supposed to lock 5 seconds after it turns itself off, but enabling the setting after being disabled gives a value of 1 second instead.

## Expected Behavior
Enabling "Lock after screen turns off" should lock the screen 5 seconds after it turns itself off (same as default).

## Steps to Reproduce
1- Open Terminal, reset light-locker lock-after-screensaver value (`gsettings reset apps.light-locker lock-after-screensaver`) and check the default value (`gsettings get apps.light-locker lock-after-screensaver`)

2- Go to Settings/Security & Privacy/Locking, disable and enable again the setting "Lock after screen turns off"

3- Open Terminal and check light-locker lock-after-screensaver value (`gsettings get apps.light-locker lock-after-screensaver`)

## Platform Information
elementary OS 5.1.7 Hera