[clang] [Clang] Don't skip capture of parameters in default arguments (PR #235529)

[via cfe-commits]

Praneeth740 wrote:

Rebased onto current main to drop unrelated history. Local testing was on an LLVM 19-based tree, not main, so I'm relying on CI. I used an AI assistant (Claude) for help on this PR and have read the contribution policies.

https://github.com/llvm/llvm-project/pull/235529