Merge "Store preferential network service config in xml" into tm-dev am: 6d8f2732 am: 80b8651a

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17643287



Change-Id: I6f9b69b16674c6457fc92b4571aac023c778633c
Ignore-AOSP-First: this is an automerge
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>