Add toString for DnsTlsServer am: bf52841c am: ea22a41b am: ac967148 am: fcc68076 am: b93b35da

Original change: https://android-review.googlesource.com/c/platform/packages/modules/DnsResolver/+/2651940



Change-Id: I34dc93f5c6435ac8b28469c371d5db806faa5022
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>