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 

const acroFormResources = params.acroForm.get("DR");
    const appearanceResources =
      this.appearance && this.appearance.dict.get("Resources");
    this._fieldResources = {
      localResources,
      acroFormResources,
      appearanceResources,
      mergedResources: Dict.merge({
        xref: params.xref,
        dictArray: [localResources, appearanceResources, acroFormResources],
        mergeSubDicts: true,
      }),
    };
    data.fieldFlags = getInheritableProperty({ dict, key: "Ff" });
    if (!Number.isInteger(data.fieldFlags) || data.fieldFlags < 0) {
      data.fieldFlags = 0;
    }
    data.readOnly = this.hasFieldFlag(AnnotationFieldFlag.READONLY);
    data.hidden = this._hasFlag(data.annotationFlags, AnnotationFlag.HIDDEN);
  }
  /**
   * Decode the given form value.
   *
   * @private
   * @memberof WidgetAnnotation
   * @param {Array<string>|Name|string} formValue - The (possibly encoded)
   *   form value.
   * @returns {Array<string>|string|null}
   */
  _decodeFormValue(formValue) {