Merge "Do not send empty TXT records" into main am: 141aac3b73 am: 326049ba10

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/3166637

Change-Id: I54685b165bb3ac316485840fcd546fdfddda7241
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>