fix iptrunk IPv6 parameters in test_create_iptrunk

/127 -> /126

test/workflows/iptrunk/test_create_iptrunk.py

@@ -194,7 +194,7 @@ def test_successful_iptrunk_creation_with_juniper_interface_names(
 ):
     mock_create_host.return_value = None
     mock_allocate_v4_network.return_value = faker.ipv4_network(max_subnet=31)
-    mock_allocate_v6_network.return_value = faker.ipv6_network(max_subnet=127)
+    mock_allocate_v6_network.return_value = faker.ipv6_network(max_subnet=126)
     product_id = get_product_id_by_name(ProductType.IP_TRUNK)
     initial_site_data = [{"product": product_id}, *input_form_wizard_data]
     result, process_stat, step_log = run_workflow("create_iptrunk", initial_site_data)