[clang] [CodeGenTypes] Preserve element type attributes within a `ConstantArrayType` (PR #211978)

[Finn Plummer via cfe-commits]

inbelic wrote:

> @inbelic I expect you will be able to close this pr now I am encoding layout on the ConstMatrixType now so it can exist without attribute sugar #214001

Yes, thanks.

https://github.com/llvm/llvm-project/pull/211978