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 fileSpecDict = new Dict(
      fileSpecDict.set("Type", Name.get("Filespec")
      fileSpecDict.set("Desc", ""
      fileSpecDict.set("EF", embeddedFileDict
      fileSpecDict.set("UF", "Test.txt"
      const fileAttachmentRef = Ref.get(20, 0
      const fileAttachmentDict = new Dict(
      fileAttachmentDict.set("Type", Name.get("Annot")
      fileAttachmentDict.set("Subtype", Name.get("FileAttachment")
      fileAttachmentDict.set("FS", fileSpecRef
      fileAttachmentDict.set("T", "Topic"
      fileAttachmentDict.set("Contents", "Test.txt"
      const xref = new XRefMock([
        { ref: fileStreamRef, data: fileStreamDict },
        { ref: fileSpecRef, data: fileSpecDict },
        { ref: fileAttachmentRef, data: fileAttachmentDict },
      ]
      embeddedFileDict.assignXref(xref
      fileSpecDict.assignXref(xref
      fileAttachmentDict.assignXref(xref
      const { data } = await AnnotationFactory.create(
        xref,
        fileAttachmentRef,
        pdfManagerMock,
        idFactoryMock
      
      expect(data.annotationType).toEqual(AnnotationType.FILEATTACHMENT
      expect(data.file.filename).toEqual("Test.txt"
      expect(data.file.content).toEqual(stringToBytes("Test attachment")
    }