When decrypt_trace_config is empty, it should be skipped directly (#15870)

api/core/ops/ops_trace_manager.py

                 provider_config_map[tracing_provider]["trace_instance"],
                 provider_config_map[tracing_provider]["config_class"],
             )
+            if not decrypt_trace_config:
+                return None
             tracing_instance = trace_instance(config_class(**decrypt_trace_config))
             return tracing_instance