Gantt duplicates requests when reordering items in the TreeList part

[nelito987]

Bug report

When tasks are reordered in Gantt duplicated requests are sent for updating.

Reproduction of the problem

1. Open the Gantt Overview Demo
2. Reorder two tasks and inspect the requests in the Network tab

Current behavior

For example, in case two tasks on the same level are changing their places, four requests are sent, two by two the requests are the same.
In case a task is moved on a different level multiple requests are sent, as all are duplicated.

Expected/desired behavior

There should be no duplicated requests when reordering tasks in Gantt

This is a regression introduced with R3 2020 (2020.3.915)

Environment

• Kendo UI version: 2021.3.914
• Browser: [all ]

[veselints]

Needs e2e test to be added in order to add the scenario in question.