Configuration:
- PDF.js version: 2.0.550

Steps to reproduce the problem:
1. Render document in SVG mode `renderMode="svg"`

What is the expected behavior? (add screenshot)
Rendering annotations same way as they rendered on canvas

What went wrong? (add screenshot)
```
Warning: Unimplemented operator beginAnnotations
Warning: Unimplemented operator endAnnotations
```
const acroForm = this.catalog.acroForm;
    if (!acroForm) {
      return null;
    }
    const xfa = acroForm.get("XFA");
    const entries = {
      "xdp:xdp": "",
      template: "",
      datasets: "",
      config: "",
      connectionSet: "",
      localeSet: "",
      stylesheet: "",
      "/xdp:xdp": "",
    };
    if (isStream(xfa) && !xfa.isEmpty) {
      try {
        entries["xdp:xdp"] = stringToUTF8String(xfa.getString());
        return entries;
      } catch (_) {
        warn("XFA - Invalid utf-8 string.");
        return null;
      }