Use default "ds512M" advance image in older stable branches (II)

This patch amends [1], setting the default advance image "ds512M" for
Designate scenario jobs in older stable branches.

Related-Bug: #1940243

[1]https://review.opendev.org/c/openstack/neutron-tempest-plugin/+/806119

Change-Id: Ied79caa66727f4df09fcbe8e4ec302c326862256
diff --git a/zuul.d/stein_jobs.yaml b/zuul.d/stein_jobs.yaml
index 037bba2..f84df2a 100644
--- a/zuul.d/stein_jobs.yaml
+++ b/zuul.d/stein_jobs.yaml
@@ -338,3 +338,5 @@
     vars:
       branch_override: stable/stein
       network_api_extensions_common: *api_extensions
+      devstack_localrc:
+        ADVANCED_INSTANCE_TYPE: ds512M