VS: Fix NVIDIA Nsight Tegra Visual Studio Edition support

The guard added by commit 8e0cb45e to Modules/Platform/Android-Determine.cmake does not work in that location because CMAKE_VS_PLATFORM_NAME is not set until after the module is loaded. Change this particular guard to test for the Visual Studio generator instead. If in the future we add support for using Visual Studio for Android without Nsight Tegra then something more will be needed, but this is good enough for now.

Closes: #16371 (closed)