Fixed test to match new error location

test/test_json_server.py

@@ -1,7 +1,10 @@
 import pytest
 from dynalab_core import Core
 from dynalab_core.config import CoreConfig
-from dynalab_core.errors import JsonServerStartupError, JsonServerTimeoutError
+from dynalab_core.protocols.json.errors import (
+    JsonServerStartupError,
+    JsonServerTimeoutError,
+)
 from test.common import find_available_port