Exclude ``NetworkWritableMtuTest`` test class in ML2/OVN

E/W packet fragmentation is not supported in ML2/OVN [1].

[1]https://docs.openstack.org/neutron/latest/ovn/gaps.html

Closes-Bug: #2082344
Change-Id: Ieeed73b2a5fc8319b3c199cdd2888e0090139077
diff --git a/zuul.d/wallaby_jobs.yaml b/zuul.d/wallaby_jobs.yaml
index 7df6876..ea64224 100644
--- a/zuul.d/wallaby_jobs.yaml
+++ b/zuul.d/wallaby_jobs.yaml
@@ -174,6 +174,8 @@
           (^neutron_tempest_plugin.scenario)|\
           (^tempest.api.compute.servers.test_attach_interfaces)|\
           (^tempest.api.compute.servers.test_multiple_create)"
+      # NOTE(ralonsoh): ``NetworkWritableMtuTest`` excluded because of https://bugs.launchpad.net/neutron/+bug/2082344
+      tempest_exclude_regex: "^neutron_tempest_plugin.scenario.test_mtu.NetworkWritableMtuTest.*"
       network_api_extensions: *api_extensions
       devstack_localrc:
         NETWORK_API_EXTENSIONS: "{{ network_api_extensions | join(',') }}"