[Confluence] Code Folding Support

Bug description

As far as I can tell, code folding is not (yet) supported in confluence output? It would be amazing to have this and I think confluence provides expand macros that could be used for this purpose?

quarto version 1.3.242

e.g. for file

---
title: "Test code folding"
format: 
  confluence-html:
    code-fold: true
---

```{r}
2 + 2
```

It looks like there's no code folding available.

Checklist

• Please include a minimal, fully reproducible example in a single .qmd file? Please provide the whole file rather than the snippet you believe is causing the issue.
• Please format your issue so it is easier for us to read the bug report.
• Please document the RStudio IDE version you're running (if applicable), by providing the value displayed in the "About RStudio" main menu dialog?
• Please document the operating system you're running. If on Linux, please provide the specific distribution.

Start with the reproducible .qmd example and the confluence-html format using code-fold: true. Compare the generated Confluence HTML with the expected expand-macro behavior described in the issue. Done means code blocks can be folded in Confluence output when code folding is enabled, while existing output remains unaffected.