Bug report

Client-side exported Excel workbooks are exported "uncompressed" (as readable text) and their size is much greater than the original document.

Regression since R2 2019 - 2019.2.514

Reproduction of the problem

1. Go to https://demos.telerik.com/kendo-ui/spreadsheet/index
2. Open the following file in Spreadsheet -
   Workbook Original.xlsx - 26 KB
3. Export the file to Excel

Current behavior

The exported file is 1015 KB in size. The content of the file may be read as plain text

Expected/desired behavior

The exported file is 26 KB or similar size. The content of the file is unreadable binary data

Environment

• Kendo UI version: 2019.2.619
• Browser: all