Merge "Revert the `fallback` naming into `default` network" am: 5f36d6f70a am: e9eab0e148

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1574083

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Ifde71b5b364c03fde902021ad7371d139677fdb1