Clean up the LinkProperties when stop monitoring sockets

The active network LinkProperties are not cleaned up after stop
socket monitoring. Then the apps will have duplicate sockets
to discover on one interface if the interface has been toggled,
because requestSocket will return both the old socket (for the
old netId that is actually gone) and a new socket on the same
interface, for the new netId. Thus, clean up the LinkProperties
when stop monitoring sockets.

Bug: 274063187
Test: atest FrameworksNetTests android.net.cts.NsdManagerTest
Change-Id: I3d600169b069a1534bd740e711bc21db107b1201