'`reboot`' invoked in container restarts its host as well

_toolbox v. 0.3_

**Description**
Hello. While in a Toolbox container a restart is requested by a component—e.g. the Linux kernel—for its pending update to apply, invoking '`reboot`' in it does restart its host as well. Could that be the intended behaviour in Podman and Toolbox?

**Expected behaviour**
The restart to take effect there where it is invoked, here therefore in the sole container; then the restart of the container not be tied to the restart of its host in order to take effect.

**Actual behaviour**
Once the host has rebooted, in that container a reboot is no longer requested, from which we can deduce that the pending update has applied, which implies that as intended a reboot took effect there.

Start by reproducing the behavior from the `reboot` entry point inside a Toolbox container, comparing it with the expected container-only restart in Podman. Trace how the request reaches the host and verify that a container reboot no longer reboots the host while still applying the pending update.

Written by the indexing model from the issue text.