Add PRIVATE_DNS_MODE setting setter am: 87ac58016f

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

Change-Id: I97de83147a0c656802601ec116ee9ee7de114884
tree: 3f1d465da7a3ba0e5e83be5715d281c0dd589f75
  1. core/
  2. framework/
  3. service/
  4. services/
  5. tests/
  6. OWNERS
  7. TEST_MAPPING