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.
if (Array.isArray(options)) {
      const xref = params.xref;
      for (let i = 0, ii = options.length; i < ii; i++) {
        const option = xref.fetchIfRef(options[i]);
        const isOptionArray = Array.isArray(option);
        this.data.options[i] = {
          exportValue: this._decodeFormValue(
            isOptionArray ? xref.fetchIfRef(option[0]) : option
          ),
          displayValue: this._decodeFormValue(
            isOptionArray ? xref.fetchIfRef(option[1]) : option
          ),
        };
      }
    }
    
    
    
    
    if (isString(this.data.fieldValue)) {
      this.data.fieldValue = [this.data.fieldValue];
    } else if (!this.data.fieldValue) {
      this.data.fieldValue = [];
    }
    
    this.data.combo = this.hasFieldFlag(AnnotationFieldFlag.COMBO);
    this.data.multiSelect = this.hasFieldFlag(AnnotationFieldFlag.MULTISELECT);
    this._hasText = true;
  }
  getFieldObject() {