[clang] CTAD alias: fix the transformation for the require-clause expr (#90961)

In the clang AST, constraint nodes are deliberately not instantiated
unless they are actively being evaluated. Consequently, occurrences of
template parameters in the require-clause expression have a subtle
"depth" difference compared to normal occurrences in places, such as
function parameters. When transforming the require-clause, we must take
this distinction into account.

The existing implementation overlooks this consideration. This patch is
to rewrite the implementation of the require-clause transformation to
address this issue.

Fixes #90177