removing hardcode

cloud_migrations/vpc-migrate-xqwatcher.yml

@@ -37,7 +37,7 @@
         tags:
           Name: "{{ edp }}-subnet"
           play: xqwatcher
-          immutable_metadata: "{'purpose':'stage-edge-internal-xqwatcher','target':'ec2'}"
+          immutable_metadata: "{'purpose':'{{ environment }}-{{ deployment }}-internal-{{ play }}','target':'ec2'}"
       with_items: subnets
       ignore_errors: True