Address leftover comments

Address leftover comments on aosp/2596565 & aosp/2593907 includes
- Rename onAllSocketsDestroyed to onSocketDestroyed
- Move SocketKey into SocketInfo
- Remove getInterfaceIndex dependency.

Bug: 278018903
Test: atest FrameworksNetTests android.net.cts.NsdManagerTest
Change-Id: Ia37804f18d8e9abbd12d4b929b71dce5fa19d4f0
10 files changed