missed cleaning up zone file outputs in mgmt accounts (#719)

Co-authored-by: Charlie Llewellyn <cjl@amazon.co.uk>

Author: charliejllewellyn

reference-artifacts/Custom-Scripts/SEA-uninstall/aws-sea-cleanup.py

@@ -90,6 +90,7 @@ def build_stack_data(accounts, regions, admin_role_name, master_account_name):
 def process_delete(all_stacks):
     phases = [        
         "-Phase5",
+        "Phase4-HostedZonesAssc1",
         "-Phase4",
         "Phase3-CentralVpcResolverEndpoints",
         "-Phase3",