[clang] [clang] Fix unresolved overloaded conversion function reference (PR #230806)

[Ivy Xu via cfe-commits]

IvyXu420 wrote:

> The first sentence mentions associated constraints so I'm not sure if only those constrained functions should apply

I don't think so. If I am understanding correctly, they are separate processes.
Looking at https://eel.is/c++draft/over.over#example-3, if only constrained functions should apply, `&X<true>::f;` and `&X<true>::g<int>;` would not be ambiguous.

https://github.com/llvm/llvm-project/pull/230806