Reduce number of request for default address
The field addresses on party has a default value.
Currently it returns the result of default_get but the client will anyway call default_get for all the fields it knows that have no default values because it does not know that we have sent all the existing default values.
Also we send default value for fields that the client may not know and so it has to fetch the definition.
This makes 3 queries by the client to get the default address.
If we sent only an empty dict than the client will call default_get for its fields. So this will make only 2 queries.