Excel files do not display grids via File preview or the Excel macro

Issue Summary

When an Excel file is uploaded to a page and/or added to the page via the Excel macro, the grids/lines are not displayed.

Steps to Reproduce

1. As a user with permission to upload attachments, upload an Excel file
2. Alternatively, after uploading it, edit the page and point the Excel macro to it.
3. Publish the page and either tap the attached file (to show the preview) or check it via the Excel macro.

Expected Results

As there are no options to hide or show grids, the file should display the grids as it is originally displayed.

Actual Results

No grids are displayed, which can cause confusion depending on the size of the file.

For colored spreadsheets, it might cause less confusion as the colors can help identify the rows/columns.

Workaround

Download the file after opening it via the file preview and check it locally.