Detection of network deps in curthooks does not handle v2 netconfig

In curthooks.install_missing_packages(), additional packages required in-target for custom network and storage configs are installed as needed based on configs. The code that handles detecting which packages will be required based on network config will not work with v2 network config, as it does not use a list of operations with 'type' keys.

Even if using netconfig passthrough to cloud-init, curtin needs to be able to determine which additional packages must be installed in the target via curthooks, so fixing this is necessary for v2 passthrough support.