[clang] [Clang][Sema] Fix crash when using name of UnresolvedUsingValueDecl with template arguments (PR #83842)

[Erich Keane via cfe-commits]

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

This seems right to me, modulo the release note/updated commit message. 

https://github.com/llvm/llvm-project/pull/83842