Bug with export excel auto format

[nsoloviev]

Prerequisites

• [x] I have searched for similar issues in both open and closed tickets and cannot find a duplicate.
• [x] The issue still exists against the latest master branch of yii2-grid.
• [x] This is not an usage question. I confirm having gone through and read the documentation and demos.
• [x] This is not a general programming / coding question. (Those should be directed to the webtips Q & A forum).
• [x] I have attempted to find the simplest possible steps to reproduce the issue.
• [ ] I have included a failing test as a pull request (Optional),

Steps to reproduce the issue

1. Set option: 'autoXlFormat' => true,
2. Set column:

   'created_at' => [
   'attribute' => 'created_at',
   'value' => function ($model) {
       return date('d.m.Y H:i:s', strtotime($model->created_at));
   },
   'format' => 'datetime',
   ],

3. Generates: <td class="w0" data-col-seq="created_at" data-raw-value="2021-01-08 16:13:24" style="mso-number-format: yyyy\-MM\-dd HH\:mm\:ss;">08.01.2021, 16:13:24</td>
4. Export to Excel

Expected behavior and actual behavior

When I follow those steps, In the Excel file, the format remains the same as in the grid

I was expecting excel format

I debugged a little and realized that this condition is always false:

  if ($td.css('mso-number-format') || $td.css('mso-number-format') === 0 ||
      $td.css('mso-number-format') === '0') {
      $td.html($td.attr('data-raw-value')).removeAttr('data-raw-value');
  }

https://github.com/kartik-v/yii2-grid/blob/master/src/assets/js/kv-grid-export.js#L376

Because $td.css('mso-number-format') is always undefined, I think because this is an unknown property

Browsers

• [x] Google Chrome
• [ ] Mozilla Firefox
• [ ] Internet Explorer
• [ ] Safari

Operating System

• [x] Windows
• [ ] Mac OS X
• [ ] Linux
• [ ] Mobile

Libraries

• jQuery version: 3.4.1
• yii2-grid version: last master

Isolating the problem

• [ ] This bug happens on the demos page
• [x] The bug happens consistently across all tested browsers
• [x] This bug happens when using yii2-grid without other plugins.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.