Custom and Text validation lost when converting to DPL workbook

[veselints]

Bug report

Custom and Text validation lost when converting to DPL workbook. The issue is in the ToDocument() logic, where only list and number rules are considered:
https://github.com/telerik/kendo/blob/master/dpl/Telerik.Web.Spreadsheet/Models/Workbook.ToDocument.cs#L221

Reproduction of the problem

• Run the following demo: https://demos.telerik.com/aspnet-mvc/spreadsheet/server-side-import-export
• Create a Custom formula validation in one of the cells using the Data > Data Validation tool. For the A3 cell the validation could be AND(LEN(A3)<3)
• Click the Save as XLSX to export the file using the Telerik.Web.Spreadsheet library
• Open the exported file in the Spreadsheet
• Select the cell for which you have defined validation and go to Data > Data Validation tool. You will notice that in the pop-up the Criteria is set to Number and the custom formula is listed in the Min field.

Expected/desired behavior

Custom validation should not be converted to Number validation upon ToDocument() call.

Environment

• Kendo UI version: 2024.1.130
• jQuery version: x.y
• Browser: [all]