fixed broken test

Author: Andrei Neagu

services/director-v2/tests/unit/with_dbs/test_modules_dynamic_sidecar_docker_service_specs.py

@@ -243,6 +243,7 @@ def expected_dynamic_sidecar_spec(
                     "FORWARD_ENV_DISPLAY": ":0",
                     "NODE_PORTS_400_REQUEST_TIMEOUT_ATTEMPTS": "3",
                     "DYNAMIC_SIDECAR_LOG_LEVEL": "DEBUG",
+                    "DYNAMIC_SIDECAR_TRACING": "null",
                     "DY_DEPLOYMENT_REGISTRY_SETTINGS": (
                         '{"REGISTRY_AUTH": false, "REGISTRY_PATH": null, '
                         '"REGISTRY_URL": "foo.bar.com", "REGISTRY_USER": '