[clang] Respect the [[clang::unsafe_buffer_usage]] attribute for constructors (PR #91777)

[Artem Dergachev via cfe-commits]

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

Aha ok everything makes sense now! I think this is good to go so LGTM! Let me see the other PR too.

https://github.com/llvm/llvm-project/pull/91777