Describe the bug

toolbox run command isn't terminated properly when terminal emulator is exited, causing processes to linger around without user's awareness.

Steps how to reproduce the behaviour

1. Open System Monitor / Task Manager equivilent in your desktop environment
2. Search for sleep
3. Execute the following command in a terminal emulator (GNOME Terminal):

toolbox run sleep 30

4. Before sleep runs out of time, try to close the terminal emulator
5. It'll prompt for something like this:

Insist closing it by pressing Close Terminal.

Expected behaviour

sleep process is terminated.

Actual behaviour

sleep keeps lingering around.

Output of toolbox --version (v0.0.90+)

toolbox version 0.0.99.3

Toolbox package info (rpm -q toolbox)

toolbox-0.0.99.3-6.fc36.x86_64

Output of podman version

Client:       Podman Engine
Version:      4.2.1
API Version:  4.2.1
Go Version:   go1.18.5
Built:        Thu Sep  8 03:58:19 2022
OS/Arch:      linux/amd64

Podman package info (rpm -q podman)

podman-4.2.1-2.fc36.x86_64

Info about your OS

Fedora Silverblue 36

Additional context

This is a screenshot which represent the issue better:

If I try to close the terminal emulator, it'll prompt the following:

If I press "Close Terminal", sh, toolbox and podman (which runs exec command) will be terminated because they're child process of the vte session.

However, notice the conmon and its child process sleep aren't part of gnome-terminal-server. When sh is terminated, podman (exec command) will be terminated but the corresponding conmon process will be kept intact. As a result, sleep 30 isn't terminated properly.

And sleep 30 is only used for demonstration. In reality one could run something resource intensive, and then close the terminal emulator not knowing they're lingering in the background.

Source: #1204