In the previous design, the network could be null for some
MdnsServiceTypeClient (tethering interfaces). However, the
MdnsMultinetworkSocketClient is designed to send packets on
specific networks. This means that if there are multiple
tethering interfaces, packets will be sent to unnecessary
sockets. Now, the MdnsServiceTypeClient is created by the socket,
which can identify which socket is the target for sending
packets. Therefore, the design should be updated to send packets
only on the specific socket.
Bug: 278018903
Test: atest FrameworksNetTests android.net.cts.NsdManagerTest
Change-Id: Id87e6d202599c57620281a6761d3c56acd2c929c
721f9b28bf