Attach (recommended) or Link to PDF file here:
[Testfile v1.5 to PDFA2.pdf](https://github.com/mozilla/pdf.js/files/6310752/Testfile.v1.5.to.PDFA2.pdf)


Configuration:
- Web browser and its version: Version 89.0.4389.114 (Offizieller Build) (x86_64)
- Operating system and its version: Windows 10 / MacOS BigSur
- PDF.js version: 2.5.207
- Is a browser extension: no 

Steps to reproduce the problem:
1.  Open Testfile v1.5 to PDFA2.pdf in pdf.js viewer demo
2. text is covered up by markings / highlights which are stored in pdf itself

What is the expected behavior? (add screenshot)
Should be displayed as in Acrobat Reader
<img width="1169" alt="Bildschirmfoto 2021-04-14 um 14 24 41" src="https://user-images.githubusercontent.com/1286150/114710202-bf175a80-9d2d-11eb-8d54-75481fe91b7d.png">

What went wrong? (add screenshot)
It's how it is displayed in pdf.js viewer
<img width="782" alt="Bildschirmfoto 2021-04-14 um 14 24 16" src="https://user-images.githubusercontent.com/1286150/114710311-d8200b80-9d2d-11eb-8000-b67b94488929.png">

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):

return new LineAnnotation(parameters);
      case "Square":
        return new SquareAnnotation(parameters);
      case "Circle":
        return new CircleAnnotation(parameters);
      case "PolyLine":
        return new PolylineAnnotation(parameters);
      case "Polygon":
        return new PolygonAnnotation(parameters);
      case "Caret":
        return new CaretAnnotation(parameters);
      case "Ink":
        return new InkAnnotation(parameters);
      case "Highlight":
        return new HighlightAnnotation(parameters);
      case "Underline":
        return new UnderlineAnnotation(parameters);
      case "Squiggly":
        return new SquigglyAnnotation(parameters);
      case "StrikeOut":
        return new StrikeOutAnnotation(parameters);
      case "Stamp":
        return new StampAnnotation(parameters);
      case "FileAttachment":
        return new FileAttachmentAnnotation(parameters);
      default:
        if (!collectFields) {
          if (!subtype) {
            warn("Annotation is missing the required /Subtype.");
          } else {