How to expose properties to scripting api

[ekolve]

I am looking to expose a few parameters in UTM to the scripting API. I took a look at a recent PR #6978 and essentially mirrored that to expose one new parameter on the apple configuration: config.virtualization.hasAudio. The changes I made are here: ekolve@da6f087

The code compiles, but the new property isn't exposed in the config to the scripting interface (I tried with a simple applescript to look at the config and it wasn't there). Any idea why that would be?