Fix -Wnullable-to-nonnull-conversion errors am: 47936dd7 am: f3aefe4f am:...

Fix -Wnullable-to-nonnull-conversion errors am: 47936dd7 am: f3aefe4f am: 4cd11bc4 am: d00eca81 am: 2fc54372 am: 2acc76a9 am: 6b64f265

Original change: https://android-review.googlesource.com/c/platform/packages/modules/DnsResolver/+/2526839



Change-Id: I8c7fc9cfde397c404232491762ac88a47659037a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>