Document swapping nested instances not working

When using a component with a nested component inside it, Figma allows you to hot swap the nested instance inside the component instance, however at the moment the importer doesn't support this and you instead get the original component.

Component instance should be detached from the component if a user wants to make further changes to it. Export should be done after that.

Concerns also: https://bugreports.qt.io/browse/QDS-3338

https://help.figma.com/hc/en-us/articles/360038665754-Detach-an-instance-from-the-component

Documentation needs to be updated.