[clang-format] FIX: Misannotation 'auto' as trailing return type in lambdas

Lambdas with trailing return type 'auto' are annotated incorrectly. It causes a misformatting. The simpliest code to reproduce is:

```
auto list = {[]() -> auto { return 0; }};
```

Fixes https://github.com/llvm/llvm-project/issues/54798

Reviewed By: HazardyKnusperkeks, owenpan, curdeius

Differential Revision: https://reviews.llvm.org/D130299