Cuda 12.9 is reported as `supported_cuda_version()` in code, but there is no lantern build for it

[cregouby]

Current Situation

lantern for cuda version 12.9 is not built right now, neither for linux, nor for windows, and is not documented in : Cuda Compatibility Matrix

But is is reported as supported thanks to

torch/R/install.R

Lines 423 to 424 in 7158384

	supported_cuda_versions_windows <- c("12.6", "12.8", "12.9")
	supported_cuda_versions_linux <- c("12.6", "12.8", "12.9")

Expected situation

Either

• add cuda 12.9 to the build chain (and change the Cuda Compatibility Matrix documentation)
  or
• change the install.R code to reflect what is actually build.