rabbitmq: Add 3.12 feature flags (for upgrade to 3.13)

As per [1].

[1]: https://rabbitmq-website.pages.dev/docs/feature-flags

Depends-On: https://review.opendev.org/c/openstack/kolla/+/911093

Change-Id: Ib5bfc99a5023e4b949c1ea38eca9bfd1ea9cd633

ansible/roles/rabbitmq/defaults/main.yml

@@ -134,5 +134,7 @@ rabbitmq_feature_flags:
   - "feature_flags_v2"
   - "direct_exchange_routing_v2"
   - "classic_mirrored_queue_version"
+  - "stream_sac_coordinator_unblock_group"
+  - "restart_streams"
 
 kolla_externally_managed_cert: False