fix for disappearinf system prompt

app.py

@@ -185,6 +185,7 @@ def instantiate_additional_settings():
     with gr.Accordion("Additional settings", open=False):
         system_message = gr.Textbox(
             label="Sytem prompt",
+            key="system_prompt",
             value="You are a helpful assistant and your name is Eliza.",
         )
     return system_message