Dynamic scaffolding generates ISO-8859-1 response for html format

Unlike rest of application and regular gsp pages dynamic scaffolding (default templates, installed or not) generates html response with HTTP header:

```
Content-Type:text/html;charset=ISO-8859-1
```

Start by reproducing the HTML response from dynamic scaffolding and inspect the default scaffolding templates and response-generation path. Done means the generated HTML response uses the application's expected charset rather than ISO-8859-1, verified by checking its HTTP Content-Type header.

Written by the indexing model from the issue text.