change to use `input` listener

Use `.input` listener, to avoid event triggered by Block.load.
ref: https://www.gradio.app/docs/gradio/textbox

app.py

@@ -3559,7 +3559,7 @@ with gr.Blocks(theme=gr.themes.Base(primary_hue=gr.themes.colors.orange, seconda
         ai_chatbot_question_3
     ]
 
-    youtube_link.change(
+    youtube_link.input(
         process_youtube_link, 
         inputs=process_youtube_link_inputs, 
         outputs=process_youtube_link_outputs