[clang] Fix recursive mangling for lambda init-captures (PR #182667)

[Tommy Chiang via cfe-commits]

oToToT wrote:

Created a new PR https://github.com/llvm/llvm-project/pull/182803 per https://llvm.org/docs/Contributing.html#:~:text=separate%20Pull%20Request

I'll rebase this PR once the NFC PR merged.

https://github.com/llvm/llvm-project/pull/182667