Attach (recommended) or Link to PDF file here:
[output.pdf](https://github.com/mozilla/pdf.js/files/6374987/output.pdf)

Configuration:
- Web browser and its version: Firefox 88.0
- Operating system and its version: macOS Big Sur 11.2.3 (20D91)
- PDF.js version: 2.8.243
- Is a browser extension: no/Firefox built-in

Steps to reproduce the problem:
1.  add Ink-Annotations to a pdf (i use https://github.com/highkite/pdfAnnotate, Annotations with appearance streams are shown correctly)
2. open output file in firefox

What is the expected behavior? 
The annotations should be visible.
![Bildschirmfoto 2021-04-26 um 09 15 48](https://user-images.githubusercontent.com/33630884/116043809-6a020f80-a670-11eb-973c-6f2df3dae532.png)

What went wrong? 
The annotations are added to the dom but invisible.
![Bildschirmfoto 2021-04-26 um 09 18 26](https://user-images.githubusercontent.com/33630884/116043867-7e460c80-a670-11eb-964d-0cc2c6dbfb61.png)

Tested successfull with FoxitReader, AcrobatReader, Chrome and Safari.
this.data.modificationDate = this.modificationDate;
      }
      this.data.hasPopup = parent.has("Popup");
      if (!parent.has("C")) {
        
        this.data.color = null;
      } else {
        this.setColor(parent.getArray("C"));
        this.data.color = this.color;
      }
    } else {
      this.data.title = stringToPDFString(dict.get("T") || "");
      this.setCreationDate(dict.get("CreationDate"));
      this.data.creationDate = this.creationDate;
      this.data.hasPopup = dict.has("Popup");
      if (!dict.has("C")) {
        
        this.data.color = null;
      }
    }
  }
  /**
   * Set the creation date.
   *
   * @public
   * @memberof MarkupAnnotation
   * @param {string} creationDate - PDF date string that indicates when the
   *                                annotation was originally created
   */
  setCreationDate(creationDate) {