ion_channel_model missing in the MEModel's EModel.

[AurelienJaquier]

The emodel in an memodel entity has ion_channel_models set to None, but when I fetch the emodel directly, then it has the ion_channel_models.

I would expect the ion_channel_models to be present in both cases.

Script to reproduce:

iterator = client.search_entity(
    entity_type=MEModel,
    token=access_token,
    limit=1,
)
memodel = next(iterator)

emodel = client.get_entity(
    entity_id=memodel.emodel.id, entity_type=EModel, token=access_token
)

print(memodel.emodel.ion_channel_models).  # gives None
print(emodel.ion_channel_models). # gives actualm list of ion channel models