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 

this.modificationDate = isString(modificationDate)
      ? modificationDate
      : null;
  }
  /**
   * Set the flags.
   *
   * @public
   * @memberof Annotation
   * @param {number} flags - Unsigned 32-bit integer specifying annotation
   *                         characteristics
   * @see {@link shared/util.js}
   */
  setFlags(flags) {
    this.flags = Number.isInteger(flags) && flags > 0 ? flags : 0;
  }
  /**
   * Check if a provided flag is set.
   *
   * @public
   * @memberof Annotation
   * @param {number} flag - Hexadecimal representation for an annotation
   *                        characteristic
   * @returns {boolean}
   * @see {@link shared/util.js}
   */
  hasFlag(flag) {