fix: Ensure networks are actually connected to pytest container
The `network` object would never be in a list of network names (strings), and without `greedy=True` arg as the `docker-py` API docs note, the containers will not be part of the results, thus always returning an empty list which was not intended..
Now the network will properly match the current networks for pytest container, avoiding duplicate connect attempts, and the network list result will actually have containers to count when filtering by length.