[automerger skipped] Fix restorePrivateDnsSetting with null hostnames am: 7fd2b373ff -s ours

am skip reason: Merged-In Ic5d8d8b729469e0eef89a0b53f166e604264c1ee with SHA-1 908b002ed2 is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/14911838

Change-Id: I6a92e80924f560b583792200743c4fcb7af2fc7f