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.
parentBuffer = [`${this.parent.num} ${this.parent.gen} obj\n`];
        writeDict(parent, parentBuffer, parentTransform);
        parentBuffer.push("\nendobj\n");
      } else if (isDict(this.parent)) {
        this.parent.set("V", name);
      }
    }
    dict.set("AS", name);
    dict.set("M", `D:${getModificationDate()}`);
    let originalTransform = null;
    if (encrypt) {
      originalTransform = encrypt.createCipherTransform(
        this.ref.num,
        this.ref.gen
      );
    }
    const buffer = [`${this.ref.num} ${this.ref.gen} obj\n`];
    writeDict(dict, buffer, originalTransform);
    buffer.push("\nendobj\n");
    const newRefs = [{ ref: this.ref, data: buffer.join(""), xfa }];
    if (parentBuffer !== null) {
      newRefs.push({
        ref: this.parent,
        data: parentBuffer.join(""),
        xfa: null,
      });
    }
    return newRefs;
  }
  _processCheckBox(params) {