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
```
partialEvaluator.xref = xref;
      const task = new WorkerTask("test save"
      const annotation = await AnnotationFactory.create(
        xref,
        buttonWidgetRef,
        pdfManagerMock,
        idFactoryMock
      
      const annotationStorage = new Map(
      annotationStorage.set(annotation.data.id, { value: true }
      let data = await annotation.save(
        partialEvaluator,
        task,
        annotationStorage
      
      expect(data.length).toEqual(2
      const [radioData, parentData] = data;
      radioData.data = radioData.data.replace(/\(D:[0-9]+\)/, "(date)"
      expect(radioData.ref).toEqual(Ref.get(123, 0)
      expect(radioData.data).toEqual(
        "123 0 obj\n" +
          "<< /Type /Annot /Subtype /Widget /FT /Btn /Ff 32768 " +
          "/AP << /N << /Checked 314 0 R /Off 271 0 R>>>> " +
          "/Parent 456 0 R /AS /Checked /M (date)>>\nendobj\n"
      
      expect(parentData.ref).toEqual(Ref.get(456, 0)
      expect(parentData.data).toEqual(
        "456 0 obj\n<< /V /Checked /Kids [123 0 R]>>\nendobj\n"
      
      annotationStorage.set(annotation.data.id, { value: false }