Use the ServiceTypeClient network for queries

Instead of the network specified in the MdnsSearchOptions, which is
often null to request searching on all networks, use the
MdnsServiceTypeClient Network to build the queries.

When MdnsSearchOptions.network is null, one MdnsServiceTypeClient is
created for each mDNS-compatible Network. Each MdnsServiceTypeClient
schedules queries with a Network selector. If the Network selector is
null, each MdnsServiceTypeClient will post its queries to all networks.
Instead, it should be the Network of the MdnsServiceTypeClient.

There is one remaining problem when a tethered interface is up: in that
case, there will be one MdnsServiceTypeClient for tethered interfaces
with a null network, which will still broadcast its queries to all
networks. This should be addressed in a follow-up by having
MdnsMultinetworkSocketClient only send queries to interfaces that have a
null network, when the network selector is null (and not all
interfaces).

Bug: 283708537
Test: atest
Change-Id: If571d7a59c5e55d809eeb1f3d1c4b58684612cdd