Answer by tanius for Disable password request from suspend - 18.04

In Ubuntu 19.04, there is finally a method to configure this without executing commands:

1. Open the "Settings" program, or start it with gnome-control-center.

2. Navigate to "Privacy" and click on "Screen locking".

3. Disable "Lock the screen in standby".

Internally, it has just the same effect as the command mentioned in another answer here:

gsettings set org.gnome.desktop.screensaver ubuntu-lock-on-suspend false