Add backup configuration options to test_llm.py

Author: CaralHsi

tests/configs/test_llm.py

@@ -27,6 +27,11 @@ def test_base_llm_config():
             "top_k",
             "remove_think_prefix",
             "default_headers",
+            "backup_client",
+            "backup_api_key",
+            "backup_api_base",
+            "backup_model_name_or_path",
+            "backup_headers",
         ],
     )