transport balance loading goes wrong when species list is unordered.

Consider a transport model with 5 species a, b,c,d and e.
When loading the balances of this model we must indicate in which balances we are interested. However, the following test fails:
`
@pytest.mark.usefixtures("flow_transport_simulation")
def test_transport_balance_loading_order_mixup(tmp_path, flow_transport_simulation):

flow_transport_simulation.write(tmp_path)
flow_transport_simulation.run()

balance_ordered = flow_transport_simulation.open_transport_budget(species_ls=["a", "b", "d"])
balance_unordered = flow_transport_simulation.open_transport_budget(species_ls=["d", "b", "a"])


assert np.all(balance_ordered.sel(species = "a")["ssm"].values == balance_unordered.sel(species = "a")["ssm"].values)

`

Start by running the pytest case test_transport_balance_loading_order_mixup with the flow_transport_simulation fixture. Read the open_transport_budget calls and compare the selected "a" balance for ordered and unordered species lists; the issue is done when the ssm values match in both cases.