[clang] [clang][Sema] Fix crash when diagnosing candidates with parameter packs (PR #93079)

[Shafik Yaghmour via cfe-commits]

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

Thank you for the fix. Can you please a little more details to your summary so that folks reading git log have more context.

This also needs a release note.

Please also add that this also fixes: https://github.com/llvm/llvm-project/issues/76354

https://github.com/llvm/llvm-project/pull/93079