Actually it is a Confirm dialog and as you can see in this video
when I click on the OK button Test Studio successfully creates a "Handle 'Confirm' dialog
" step. The only tricky thing here is that you need to add the Button manually to the Elements Explorer and add a click step from the step suggestion as seen in the video. This is because it is a child element of the Kendo Grid Cell. I have attached the sample test from the video. Please give it a try and let me know if you need further assistance on this.
the Telerik team