Fix issue with stop if queued

ui.py

@@ -66,7 +66,7 @@ class UIController:
     @staticmethod
     def stop_process(engine: FunctionGemmaEngine) -> str:
         engine.trigger_stop()
-        return "Stopping..."
+        return
 
     @staticmethod
     def zip_model(engine: FunctionGemmaEngine) -> Any:
@@ -330,7 +330,9 @@ def build_interface() -> gr.Blocks:
         stop_btn.click(
             fn=UIController.stop_process,
             inputs=[engine_state],
-            cancels=[train_run_event, eval_run_event]
+            cancels=[train_run_event, eval_run_event],
+            outputs=None,
+            queue=False
         )
 
         reload_btn.click(lock_ui, outputs=action_buttons + [push_btn, zip_btn]).then(