Set DNS_ADDRESS to empty string instead of delete

Kustomize strategic merge cannot properly delete env var from base.
Setting to empty string allows DOT configuration to work.

Author: sofmeright

fluxcd/apps/overlays/production/cross-seed/statefulset-patch.yaml

@@ -119,6 +119,8 @@ spec:
           value: "2468,6887,9696"
         - name: FIREWALL_OUTBOUND_SUBNETS
           value: "10.0.0.0/8,172.16.0.0/12,172.22.30.33/32"
+        - name: DNS_ADDRESS
+          value: ""
         - name: DNS_KEEP_NAMESERVER
           value: "off"
         - name: DOT