[C++] Don't filter using declaration when we perform qualified look up

Close https://github.com/llvm/llvm-project/issues/62174

And this was originally a try to close
https://github.com/llvm/llvm-project/issues/62158.

I don't feel this is the correct fix. I just think it is not bad as an
ad-hoc patch. And let's discuss things in the higher-level in the above
GitHub issue link.

Reviewed By: erichkeane

Differential Revision: https://reviews.llvm.org/D148506