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.
lastSpacePosInStringStart = start;
          lastSpacePosInStringEnd = end;
          lastSpacePos = i;
        }
      } else {
        if (currentWidth + glyphWidth > width) {
          
          if (lastSpacePosInStringStart !== -1) {
            chunks.push(line.substring(startChunk, lastSpacePosInStringEnd));
            startChunk = lastSpacePosInStringEnd;
            i = lastSpacePos + 1;
            lastSpacePosInStringStart = -1;
            currentWidth = 0;
          } else {
            
            chunks.push(line.substring(startChunk, start));
            startChunk = start;
            currentWidth = glyphWidth;
          }
        } else {
          currentWidth += glyphWidth;
        }
      }
    }
    if (startChunk < line.length) {
      chunks.push(line.substring(startChunk, line.length));
    }
    return chunks;
  }
  getFieldObject() {