prevent multiple db send on login

app.py

@@ -259,6 +259,7 @@ with gr.Blocks() as demo:
             login,
             [username_input, email_input, session],
             [output_text, session, login_block, user_block],
+            trigger_mode="once",
         )
 
 demo.launch(allowed_paths=["./images/eHwhite.png", "eHwhite.png", "./images/pp.png"])