[clang] [HLSL][Matrix] Add implicit type conversions for constant matrix types (PR #181939)

[Farzon Lotfi via cfe-commits]

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

This LGTM.  I would like you to confirm though if we are maybe applying the type adjustment unnecessqrily if the to and from are both `ConstantMatrixType`.

https://github.com/llvm/llvm-project/pull/181939