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.

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    if (sign === -1 && bCurrencyPrepend && negStyle === 0) {
      buf.push("-");
    }
    if ((negStyle === 2 || negStyle === 3) && sign === -1) {
      buf.push("(");
      hasParen = true;
    }
    if (bCurrencyPrepend) {
      buf.push(strCurrency);
    }
    
    sepStyle = Math.min(Math.max(0, Math.floor(sepStyle)), 4);
    buf.push("%,", sepStyle, ".", nDec.toString(), "f");
    if (!bCurrencyPrepend) {
      buf.push(strCurrency);
    }
    if (hasParen) {
      buf.push(")");
    }
    if (negStyle === 1 || negStyle === 3) {
      event.target.textColor = sign === 1 ? this._color.black : this._color.red;
    }
    if ((negStyle !== 0 || bCurrencyPrepend) && sign === -1) {
      value = -value;
    }
    const formatStr = buf.join("");
    event.value = this._util.printf(formatStr, value);
  }
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