Kendo Observable is missing properties in TypeScript 3.9

[veselints]

Bug report

Due to the following change in TypeScript (microsoft/TypeScript#32264 (comment)), in some scenarios, the Kendo observable is missing properties in TypeScript 3.9.

Reproduction of the problem

Steps to reproduce the issue are present in Support thread 1480700

Expected/desired behavior

Observable creation logic should not rely on the enumeration of property definitions.

Environment

• Kendo UI version: 2020.2.617

[benpetermorris]

This is a significant problem for everyone using TypeScript + Kendo; without a workaround, upgrading to TypeScript 3.9 is impossible. Please reconsider the severity assigned to this issue.