### Bug report

When the footerTemplate option of the TreeList is specified for a column that is part of a multi-column header configuration, the template is not rendered.

### Reproduction of the problem

1. Set a footerTemplate option for the nested column. Dojo sample for reproduction:

https://dojo.telerik.com/iKisAZaS/16

### Environment

* **Kendo UI version:** 2020.1.219
* **jQuery version:** 1.12.4
* **Browser:** [all ]