Merge "Add a unit test for a bug in registerDefaultNetworkCallback." am: b8178678df am: eabf1851e8 am: 672124e854

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

Change-Id: I40eec4d2efbaf472d4c69944952672928b185361