[automerge] Move some utility methods to MdnsUtils 2p: 64732f379f am: 66b1a96a66

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/23074355

Change-Id: I81768278002209bb1190db4f1169def65b705877
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>