If there is no request for all networks, the tethered/local only
interface changes will be ignored. However, these available
interfaces are not used for mDNS when a user requests a socket
with a null network because the interfaces are lost due to the
previous ignore. Therefore, the interface changes should be
retained and will be used for socket creations afterwards.
Bug: 284939720
Test: atest FrameworksNetTests android.net.cts.NsdManagerTest
Change-Id: If830eb53af26f21f497314477b131ce28468a971
bb69412f5b