Restore some snn network checks.

[a-t-0]

# Assert no duplicate edges exist.
    assert_no_duplicate_edges_exist(G)

    # Assert all neuron properties are specified.
    verify_networkx_snn_spec(G, t=0, backend="nx")

    # Generate networkx network.
    add_nx_neurons_to_networkx_graph(G, t=0)

    if not isinstance(G, nx.DiGraph):
        raise Exception(
            "Error, the snn graph is not a networkx graph anymore:"
            + f"{type(G)}"
        )

    # TODO: add lava neurons if run config demands lava.
    # Generate lava network.
    # add_lava_neurons_to_networkx_graph(G)

    # Verify the simulations produce identical static
    # neuron properties.
    # compare_static_snn_properties(self, G)