Provide basic CSS formatting for markdown rendered in description fields for the sandbox
### Issue Description

Markdown is supported and rendered correctly in the sandbox but it seems the reset.css is removing some of the default styles the browser would apply. It would be great to add some basic styles for things like tables and use the browsers defaults as much as possible here.

| Default    | Example with some minor CSS applied |
| -------- | ------- |
| <img width="558" alt="image" src="https://github.com/apollographql/apollo-server/assets/6160732/a16503bc-9d35-45f2-9d29-43bdfd5d4a37"> | <img width="555" alt="image" src="https://github.com/apollographql/apollo-server/assets/6160732/88c961d7-7207-46ba-a3a2-aa41c4ae2f9f"> |





### Link to Reproduction

[CodeSandbox](https://codesandbox.io/p/devbox/brave-forest-76pjwj?file=%2Fsrc%2Findex.js)

### Reproduction Steps

You can view the [default rendered markdown here](https://codesandbox.io/p/devbox/brave-forest-76pjwj?file=%2Fsrc%2Findex.js) in the query description