Attach (recommended) or Link to PDF file here: [form-cms1500.pdf](https://github.com/mozilla/pdf.js/files/5670936/form-cms1500.pdf) (Original opened in Acrobat and checked one radio-button)
Original Source: https://www.cigna.com/static/www-cigna-com/docs/health-care-providers/form-cms1500.pdf

Configuration:
- Web browser and its version: FF 83.0
- Operating system and its version: Win 10 Pro
- PDF.js version: 2.7.355

Steps to reproduce the problem:
1. Open the PDF here: https://mozilla.github.io/pdf.js/web/viewer.html
2. See that all radio-buttons are checked, which is wrong.

What is the expected behavior? (add screenshot)
![grafik](https://user-images.githubusercontent.com/12390057/101734698-f72d3900-3ac0-11eb-817e-94ce276797e8.png)

What went wrong? (add screenshot)
![grafik](https://user-images.githubusercontent.com/12390057/101734712-fc8a8380-3ac0-11eb-833d-412243a7950c.png)

This radio-button field can be found in object `45 0 obj`.
elementData.userValue = detail.value || "";
              storage.setValue(id, { value: elementData.userValue.toString() });
              if (!elementData.formattedValue) {
                event.target.value = elementData.userValue;
              }
            },
            valueAsString() {
              elementData.formattedValue = detail.valueAsString || "";
              if (event.target !== document.activeElement) {
                
                event.target.value = elementData.formattedValue;
              }
              storage.setValue(id, {
                formattedValue: elementData.formattedValue,
              });
            },
            focus() {