Do not evaluate dependent immediate invocations

We deferred the evaluation of dependent immediate invocations in https://reviews.llvm.org/D119375 until instantiation.
We should also not consider them referenced from a non-consteval context.

Fixes: https://github.com/llvm/llvm-project/issues/55601

```
template<typename T>
class Bar {
  consteval static T x() { return 5; }
 public:
  Bar() : a(x()) {}

 private:
  int a;
};

Bar<int> g();
```
Is now accepted by clang. Previously it errored with: `cannot take address of consteval function 'x' outside of an immediate invocation  Bar() : a(x()) {}`

Differential Revision: https://reviews.llvm.org/D132031