firewalld zone not set for open networks

Software environment

• Operating system: n/a
• Architecture: n/a
• kernel version: n/a
• libvirt version: 7.6.0 and probably others
• Hypervisor and version: n/a

Description of problem

Per title the firewalld zone for an open network will not be set, neither to the default libvirt zone nor to any zone attribute value of the bridge element: https://gitlab.com/libvirt/libvirt/-/blob/master/src/network/bridge_driver.c#L2392

This contradicts the documentation which states: The optional zone attribute of the bridge element is used to specify the firewalld zone for the bridge of a network with forward mode of "nat", "route", "open", or one with no forward specified.

Steps to reproduce

1. Define an open network
2. Start the defined network

Additional information

Please make the documentation and the code consistent, preferably by setting the zone for open networks as they are otherwise unusable in an environment with firewalld installed.