To minimize direct construction of BasicPortAllocator, network emulation manager api is changed to push toward injecting network dependencies to PeerConnectionFactory and let it create PortAllocator Bug: webrtc:42232556 Change-Id: I0c86d797a97d543c2f033286281dc1145d4ef51b Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/376880 Commit-Queue: Danil Chapovalov <danilchap@webrtc.org> Reviewed-by: Per Kjellander <perkj@webrtc.org> Cr-Commit-Position: refs/heads/main@{#43872}