Attach (recommended) or Link to PDF file here: 
[A Sample PDF Clean 0 degree with all annotations-original-rotated.pdf](https://github.com/mozilla/pdf.js/files/6551789/A.Sample.PDF.Clean.0.degree.with.all.annotations-original-rotated.pdf)

Configuration:
- Web browser and its version: all browsers, tested with Chrome and Firefox latest versions.
- Operating system and its version: tested in Windows 10
- PDF.js version: current (online version)

Steps to reproduce the problem:
1. Visit https://mozilla.github.io/pdf.js/web/viewer.html
2. Upload the file above
3. Notice that several annotations such as arrow, freehand & polyline are missing (compared to Acrobat Reader)
![image](https://user-images.githubusercontent.com/45581023/119781014-11d35d00-befd-11eb-8daa-64f15374cf5b.png)


What is the expected behavior?
- Should display all annotations accordingly to Acrobat Reader

What went wrong? 
- Several annotations are missing such as arrow, freehand & polyline
- Opacity property is not supported and cannot be retrieved via getAnnotations 

if (renderForms && !(this instanceof SignatureWidgetAnnotation)) {
      return Promise.resolve(new OperatorList());
    }
    if (!this._hasText) {
      return super.getOperatorList(
        evaluator,
        task,
        renderForms,
        annotationStorage
      );
    }
    return this._getAppearance(evaluator, task, annotationStorage).then(
      content => {
        if (this.appearance && content === null) {
          return super.getOperatorList(
            evaluator,
            task,
            renderForms,
            annotationStorage
          );
        }
        const operatorList = new OperatorList();
        
        
        if (!this._defaultAppearance || content === null) {
          return operatorList;