Always save network module type to metadata

I'm thinking it would be a good idea to always save the network module type to the metadata because that allows the models list in additional_networks to be filtered based on that metadata. Without it it's too easy to choose a non-locon model

Start by locating the metadata-writing path for network modules and the additional_networks model-list filtering. The change is complete when the network module type is always saved in metadata and the list can distinguish non-locon models from locon models.

Written by the indexing model from the issue text.