NetworkDiscovery test makes incorrect assumptions

[Geod24]

The first test in NetworkDiscovery uses the return of getNodeInfo: https://github.com/bpfkorea/agora/blob/81e348264c54ce951b9b09a73f096426c271d6b9/source/agora/test/NetworkDiscovery.d#L32-L33

This returns the set of known addresses which doesn't necessarily includes addresses we are connected to. https://github.com/bpfkorea/agora/blob/81e348264c54ce951b9b09a73f096426c271d6b9/source/agora/network/Manager.d#L1036-L1043

For example: https://github.com/bpfkorea/agora/blob/81e348264c54ce951b9b09a73f096426c271d6b9/source/agora/network/Manager.d#L743-L748

Found while working on https://github.com/bpfkorea/agora/pull/1737