Update app.py

app.py

@@ -193,7 +193,7 @@ def build_demo(embed_mode, concurrency_count=1):
                         ["./examples/safari_google.png", "Click on search bar."],
                         ["./examples/apple_music.png", "Star to favorite."],
                         ["./examples/app_store.png", "Download Kindle."],
-                        ["./examples/ios_setting.png", "Turn off Do not disturb"."],
+                        ["./examples/ios_setting.png", "Turn off Do not disturb."],
                         ["./examples/map.png", "Boston."],
                         ["./examples/wallet.png", "Scan a QR code."],
                         ["./examples/web_forum.png", "Post my comment."],