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 textWidgetRef = Ref.get(123, 0
      const xref = new XRefMock([
        { ref: textWidgetRef, data: textWidgetDict },
        gothRefObj,
      ]
      partialEvaluator.xref = xref;
      const task = new WorkerTask("test save"
      const annotation = await AnnotationFactory.create(
        xref,
        textWidgetRef,
        pdfManagerMock,
        idFactoryMock
      
      const annotationStorage = new Map(
      annotationStorage.set(annotation.data.id, {
        value: "こんにちは世界の",
      }
      const data = await annotation.save(
        partialEvaluator,
        task,
        annotationStorage
      
      const utf16String =
        "\x30\x53\x30\x93\x30\x6b\x30\x61\x30\x6f\x4e\x16\x75\x4c\x30\x6e";
      expect(data.length).toEqual(2
      const [oldData, newData] = data;
      expect(oldData.ref).toEqual(Ref.get(123, 0)
      expect(newData.ref).toEqual(Ref.get(2, 0)
      oldData.data = oldData.data.replace(/\(D:[0-9]+\)/, "(date)"
      expect(oldData.data).toEqual(