Keep ovn in dependecies.dynamic.targeted

Once this upstream patch https://review.opendev.org/c/openstack/openstack-helm-infra/+/889990/
merged, no need to keep this empty section in the values.
diff --git a/charts/neutron/values.yaml b/charts/neutron/values.yaml
index 122d912..423748c 100644
--- a/charts/neutron/values.yaml
+++ b/charts/neutron/values.yaml
@@ -158,6 +158,7 @@
       sriov: {}
       l2gateway: {}
       bagpipe_bgp: {}
+      ovn: {}
       openvswitch:
         dhcp:
           pod: