[clang] [Clang][Sema] Use StructuralValues to model dependent NTTP arguments (PR #93556)

[Erich Keane via cfe-commits]

https://github.com/erichkeane commented:

This change seems smaller than I expected here, so I guess I'm not entirely sure what is going on.  Can you better explain how this ends up using structural values instead of the TemplateParamObjectDecl?

https://github.com/llvm/llvm-project/pull/93556