Replace deprecated tenant_id property

The tenant_id property of RestClient in tempest was deprecated in
25.0.0. This replaces the deprecated property by the new project_id
property to avoid the following warning.

WARNING tempest.lib.common.rest_client [-] Deprecated: "tenant_id"
property is deprecated for removal, use "project_id" instead

Depends-on: https://review.opendev.org/c/openstack/tempest/+/707938
Change-Id: Ie3c32f9f2278b78603a4214c5717df8691ba490a
diff --git a/neutron_tempest_plugin/scenario/test_migration.py b/neutron_tempest_plugin/scenario/test_migration.py
index 410c64e..3c0d384 100644
--- a/neutron_tempest_plugin/scenario/test_migration.py
+++ b/neutron_tempest_plugin/scenario/test_migration.py
@@ -125,7 +125,7 @@
     def _test_migration(self, before_dvr, before_ha, after_dvr, after_ha):
         router = self.create_router_by_client(
             distributed=before_dvr, ha=before_ha,
-            tenant_id=self.client.tenant_id, is_admin=True)
+            tenant_id=self.client.project_id, is_admin=True)
 
         self.setup_network_and_server(router=router)
         self._wait_until_router_ports_ready(