[Clang][Sema] Allow access to a public template alias declaration that refers...

[Clang][Sema] Allow access to a public template alias declaration that refers to friend's private nested type (#83847)

This patch attempts to fix
https://github.com/llvm/llvm-project/issues/25708


Current access check missed qualifier(`NestedNameSpecifier`) in friend
class checking. Add it to `Records` of `EffectiveContext` by changing
the `DeclContext` makes `MatchesFriend` work.

Co-authored-by: huqizhi <836744285@qq.com>