Add domain proxy prefix to env variables.

Author: tecarter94

deploy/tasks/buildah-oci-ta.yaml

@@ -441,7 +441,7 @@ spec:
             unshare -Ufp --keep-caps -r --map-users 1,1,65536 --map-groups 1,1,65536 -- buildah pull $image
           done
           echo "Build will be executed with network isolation"
-          if [ "${DOMAIN_PROXY}" == "true" ]; then
+          if [ "${ENABLE_DOMAIN_PROXY}" == "true" ]; then
             use_domain_proxy=true
             echo "Build will be executed with domain proxy"
             /app/domain-proxy-server &