Merge "Add a unit test for a bug in registerDefaultNetworkCallback." am: b8178678df am: eabf1851e8 am: 0c0b45e6b5 am: 0ceaf95f24

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1796367

Change-Id: I346228233bac4986f08bd077abb135a3dd738e06