[clang] [Clang][Sema] Refactor collection of multi-level template argument lists (PR #106585)

[Krystian Stasiowski via cfe-commits]

sdkrystian wrote:

> Also, do you plan to fix #102320 in this or the follow-up patches?

@zyn0217 This patch (in its current state) fixes #102320 :)

https://github.com/llvm/llvm-project/pull/106585