Add MDnsManager am: 541b72d03b am: bab37e7ac2

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2049244

Change-Id: I748edb3ebf3e8c4b36cff7a6e41f3f93dd957931
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>