Copy button doesn't work in dartpad in api doc page in api.flutter.dev

[chunhtai]

Page URL

https://api.flutter.dev/flutter/widgets/CustomScrollView-class.html

Page source

No response

Describe the problem

Using chrome on macOS

1. click the copy button

notice it doesn't work and crashes the app

Expected fix

No response

Additional context

No response

I would like to fix this problem.

• [ ] I will try and fix this problem on docs.flutter.dev.