Merge "Add a NetworkAgent API to indicate that a network will be replaced." am: 9f6e6c4e27 am: 69856b3004 am: a3251c4a19

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1987457

Change-Id: I029ebd5aec444b28bdc02b6f1541268ba1e88f75