### Bug report
The Column.Exportable option is not correctly serialized and cannot be used to export hidden columns.
### Reproduction of the problem
1. Set Column.Exportable(true) and Column.Hidden(true).
2. Export the grid and see that the column is not present in the exported file.
### TicketID:
1543405
### Environment
* **Kendo UI version:** 2021.3.1109
* **jQuery version:** 1.12.4
* **Browser:** [all]