[Concepts] Traverse the instantiation chain for parameter injection inside a constraint scope (#79568)

We preserve the trailing requires-expression during the lambda
expression transformation. In order to get those referenced parameters
inside a requires-expression properly resolved to the instantiated
decls, we intended to inject these 'original' `ParmVarDecls` to the
current instantiaion scope, at `Sema::SetupConstraintScope`.

The previous approach seems to overlook nested instantiation chains,
leading to the crash within a nested lambda followed by a requires
clause.

This fixes https://github.com/llvm/llvm-project/issues/73418.

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