Update SaveKpiResult to correctly handle itemVersion value ranges

Description

The web project's SaveKpiResult method in the TestingController is trying to parse itemVersion from the posted data into an int16, even though the itemVersion coming from the test can be up to int32. This can cause parse errors where there shouldn't be any.

To reproduce: create a test with the Time On Page KPI and for content with a version id that is greater than an int 16, but less than an int 32. When going to the page, it returns a 400 bad request error.