[clang] [HLSL] Desugar ConstantArrayType when calculating cbuffer field layout (PR #134683)

[Helena Kotas via cfe-commits]

https://github.com/hekota approved this pull request.

LGTM! One suggestion to use `getUnqualifiedDesugaredType` instead of `getDesugaredType` that requires a context.

https://github.com/llvm/llvm-project/pull/134683