Add CACHE when unsetting CMAKE_CUDA_ARCHITECTURES to ensure it's empty

[jmcarcell]

Description

Add CACHE when unsetting CMAKE_CUDA_ARCHITECTURES to ensure it's empty.

Motivation and Context

Recently, when building passing CMAKE_CUDA_ARCHITECTURES=all configuring fails because CMAKE_CUDA_ARCHITECTURES is not being correctly unsetted and then set to the curated list of architectures.
Error message:

-- Setting CMAKE_CUDA_ARCHITECTURES to all enables a list of architectures OnnxRuntime optimized for, not all architectures CUDA compiler supports.
CMake Error at external/cuda_configuration.cmake:154 (message):
  Unrecognized CUDA architecture: all
Call Stack (most recent call first):
  CMakeLists.txt:715 (setup_cuda_architectures)


-- Configuring incomplete, errors occurred!

I got this error both on Alma 9 and Ubuntu 24.04 and after this change the build starts to compile.