I noticed that you have referenced both:
The latter is served by the REST Service in our newer versions and generally, you don't need to reference it. It is also a subset of 'kendo.all.min.js', hence it is not necessary to reference it when you have referenced 'kendo.all.min.js'.
I pasted your code in a new web page in our Html5 Viewer demo and reproduced a similar error related to 'HTMLSelectElement.pageSize'. When I removed the reference to 'telerikReportViewer.kendo-126.96.36.199.min.js' both the Kendo Grid and the Telerik Report Viewer were displayed.
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