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
```
buttonWidgetRef,
        pdfManagerMock,
        idFactoryMock
      
      const annotationStorage = new Map(
      const data = await annotation.save(
        partialEvaluator,
        task,
        annotationStorage
      
      expect(data).toEqual(null
    }
    it("should handle push buttons", async function () {
      const buttonWidgetRef = Ref.get(124, 0
      buttonWidgetDict.set("Ff", AnnotationFieldFlag.PUSHBUTTON
      const actionDict = new Dict(
      actionDict.set("S", Name.get("JavaScript")
      actionDict.set("JS", "do_something("
      buttonWidgetDict.set("A", actionDict
      const xref = new XRefMock([
        { ref: buttonWidgetRef, data: buttonWidgetDict },
      ]
      const { data } = await AnnotationFactory.create(
        xref,
        buttonWidgetRef,
        pdfManagerMock,
        idFactoryMock
      
      expect(data.annotationType).toEqual(AnnotationType.WIDGET
      expect(data.pushButton).toEqual(true