[Backport release-1.18] Silence benign grpc.aio noise

[dapr-bot]

Backport of #1127 to release-1.18.

Backporting failed due to merge conflicts. Please resolve manually:

git fetch origin
git checkout backport-1127-to-release-1.18

# Reset to base, discarding the empty placeholder commit
git reset --hard origin/release-1.18

# Cherry-pick the merged commit
git cherry-pick -x -m 1 78ff8b194db44eb6d28e2b35e34df12bc6dd718e

# Resolve the conflicts, then:
git add .
git cherry-pick --continue

# Force-push to replace the placeholder commit
git push --force-with-lease origin backport-1127-to-release-1.18