refactor(tazjin/dns): Add zone validity checks in CI

Same as //ops/dns

Change-Id: I0399efd2e48956ec91833386adff27d94d08ef1e
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3013
Tested-by: BuildkiteCI
Reviewed-by: tazjin <mail@tazj.in>

users/tazjin/cloud-dns/import

@@ -1,11 +0,0 @@
-#!/bin/sh
-set -ue
-
-# Imports a zone file into a Google Cloud DNS zone of the same name
-readonly ZONE="${1}"
-
-gcloud dns record-sets import "${ZONE}" \
-       --project composite-watch-759 \
-       --zone-file-format \
-       --delete-all-existing \
-       --zone "${ZONE}"