[clang] [Clang][Sema] Mark decomposition decl invalid for explicit array type (PR #210964)

[Yanzuo Liu via cfe-commits]

zwuis wrote:

> An alternative approach might be to 'fixit' the type to `auto`/the deduced type and let it go from there.

BTW I think this is a good approach for #222605.

https://github.com/llvm/llvm-project/pull/210964