CUDA 12.8 & 12.9 + MSVC CI CUDA < 12.4

[ptheywood]

• Updates the CMake warnings when cuda support is not found on windows to include the new workaround and be more consistent
• Uses NVCC_PREPEND_FLAGS on CI for CUDA < 12.4 with MSVC on CI, including CUDA 11.6, 11.8 and 12.0.
• Adds CUDA 12.6.1-12.9.1 to the known cuda downloads on windows
• Updates the "latest" CUDA in CI to use 12.9, and on ubuntu uses SM_120 (consumer blackwell) for one workflow to check compatibility.
  • Also standardises CUDA versions across workflows.
    • 11.2/11.6/11.7, 11.8, 12.0 & 12.9 for regular CI
    • 11.2 and 12.0 for linux wheels.
    • 11.6 and 12.0 for windows wheels (oldest possible even with workaround)

Closes #1274
Part of #1292