Destroy networks as soon as they are disconnected.

...as opposed to after the async channel finished disconnecting.

Clean cherry-pick of ag/4043255

Bug: 78308259
Test: runtest frameworks-net
      also used a device with this patch over the weekend and
      tried all I could think of
Merged-In: Ic4c7520e907de353a01c2a3a8a50d661dee4a994
Merged-In: I0617f0ff6e46a1d3764335a1e7ad01b34c8cc5a8

Change-Id: I4e4b41bbdf25d7d7bea4124cb58da004d47f1090