Revert "Mark test_subport_connectivity as unstable for now"

This reverts commit c12b50cac6814bf4210b7d94fb3a1a7dc762e977.

Reason for revert: Good success rate in master and stable branches,
400+ success seen in last 14 days as per opensearch.
There was one failure in ubuntu jammy job but that's a known issue.

Change-Id: I3cc3915c9008067690af85b381db2f4acbbf47b0
Related-Bug: #1897796
Conflicts:
	neutron_tempest_plugin/scenario/test_trunk.py
diff --git a/neutron_tempest_plugin/scenario/test_trunk.py b/neutron_tempest_plugin/scenario/test_trunk.py
index d4fcf6f..66e6254 100644
--- a/neutron_tempest_plugin/scenario/test_trunk.py
+++ b/neutron_tempest_plugin/scenario/test_trunk.py
@@ -316,7 +316,6 @@
                                          vlan_subnet=vlan_subnet)
             self._check_servers_remote_connectivity(vms=vms)
 
-    @test.unstable_test("bug 1897796")
     @testtools.skipUnless(
         (CONF.neutron_plugin_options.advanced_image_ref or
          CONF.neutron_plugin_options.default_image_is_advanced),