[clang] [Sema] LambdaScopeForCallOperatorInstantiationRAII - fix typo in early out logic (PR #96888)

[Simon Pilgrim via cfe-commits]

RKSimon wrote:

It would probably explain why the typo hasn't caused regression - I'm going off static analysis reports here, not crash reports.

https://github.com/llvm/llvm-project/pull/96888