Hi pdfjs team,

Please find attach a really simple pdf file to reproduce the issue.
[Date.pdf](https://github.com/mozilla/pdf.js/files/8242310/Date.pdf)
This pdf contains 4 date fields, One with a default format (dd/mm/yyyy) and the 3 others with custom formats:

    -  dd
    -  mm
    -  yyyy

The expected behavior is that whenever I fill dd field with 16 for instance, then when i focus out that field the value displayed is 16 but I get 01.

This happens for dd field and mm but it's working fine for dd/mm/yyyy and yyyy fields.

The initial values of the pdf are properly displayed, this happens only if I focus one of those fields.

Thank you for your time

Best regards.

},
      d: data => {
        return data.day.toString();
      },
      yyyy: data => {
        return data.year.toString();
      },
      yy: data => {
        return (data.year % 100).toString().padStart(2, "0");
      },
      HH: data => {
        return data.hours.toString().padStart(2, "0");
      },
      H: data => {
        return data.hours.toString();
      },
      hh: data => {
        return (1 + ((data.hours + 11) % 12)).toString().padStart(2, "0");
      },
      h: data => {
        return (1 + ((data.hours + 11) % 12)).toString();
      },
      MM: data => {
        return data.minutes.toString().padStart(2, "0");
      },
      M: data => {
        return data.minutes.toString();
      },
      ss: data => {
        return data.seconds.toString().padStart(2, "0");