[clang] [clang][Sema] Fix a bug when instantiating a lambda with requires clause (PR #65193)

[via cfe-commits]

https://github.com/cor3ntin commented:

We have `addInstantiatedParametersToScope` - Which we use in SetupConstraints` for example
We could reuse that to add the parameter of the enclosing function.
We could similarly add an `addInstantiatedLocalVarsToScope` method doing the same thing.

And the logic could be moved to `LambdaScopeForCallOperatorInstantiationRAII`

@erichkeane for additional feedback

https://github.com/llvm/llvm-project/pull/65193