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.

this._document = document;
    this._app = app;
    this._util = util;
    this._color = color;
    this._dateFormats = [
      "m/d",
      "m/d/yy",
      "mm/dd/yy",
      "mm/yy",
      "d-mmm",
      "d-mmm-yy",
      "dd-mmm-yy",
      "yy-mm-dd",
      "mmm-yy",
      "mmmm-yy",
      "mmm d, yyyy",
      "mmmm d, yyyy",
      "m/d/yy h:MM tt",
      "m/d/yy HH:MM",
    ];
    this._timeFormats = ["HH:MM", "h:MM tt", "HH:MM:ss", "h:MM:ss tt"];
    
    
    this._emailRegex = new RegExp(
      "^[a-zA-Z0-9.!#$%&'*+\\/=?^_`{|}~-]+" +
        "@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?" +
        "(?:\\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$"
    );
  }
  _mkTargetName(event) {