Elaborate error message for amp-script with attribute data-ampdevmode #29457
Description
In #27076, we made it legal to use data-ampdevmode on an <amp-script> component even if the attribute was not included on the root html node. An example:
<html ⚡ lang="en">
...
<amp-script layout="fixed" height="300" width="200" data-ampdevmode>
...
</html>This approach works! However, it throws a validation error in the Chrome extension, even though it doesn't throw one in the Console:
The attribute 'data-ampdevmode' in tag 'amp-script' is set to the invalid value ''.
