[automerger skipped] Merge "Support learning the NAT64 prefix from two different sources." into rvc-dev am: 4f7f6d67 am: f349dec0 am: cd7a48e6 am: 147f90bd -s ours am: eabd811e -s ours

am skip reason: Change-Id Ic7452431d2d9aea1ae59b67a9d8383c6cc5b3902 with SHA-1 1cb345e7 is in history

Change-Id: I3acc60b8402f27d61e74f156c77329d20edc939f