[automerger skipped] Add PRIVATE_DNS_MODE setting setter am: 5dfacdee am: f8215991 am: f7b4e3d0 -s ours am: 15c76913 -s ours

am skip reason: skip tag Change-Id If234426f041606c4881de1eca31b6f5bdb3c6bfe with SHA-1 37135512 is already in history

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1654014

Change-Id: Ic568a343d3dd30f5865e85b0fd1770c722e87b99