VS: Fix compiler identification of nvcc with unsupported host compiler

Brad Kingrequested to merge
brad.king/cmake:cuda-vs-17.10 into master

nvcc from CUDA < 12.4 does support the MSVC 14.40.17.10 toolset. Users may specify CUDAFLAGS=-allow-unsupported-compiler to bypass the check. However, we do not use arbitrary user-specified flags during compiler identification in the VS generator because escaping them for the AdditionalOptions of the .vcxproj file requires non-trivial logic that we currently only implement in the C++ generator code. Instead, just always pass -allow-unsupported-compiler during CUDA compiler identification in the VS generator.

Fixes: #26003 (closed)
Backport: release

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