Merge "Add VcnUnderlyingNetworkSpecifier" am: a7d23702bf am: f08e1215d2 am: 2d3fad77b6

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1577283

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I7535e67907c28c7b394492407c25f8afd06dbd58