[clang] [clang-format] Skip PP directives when determining brace kind (PR #69473)

[Emilia Kond via cfe-commits]

rymiel wrote:

Here's my solution to the regression I caused (https://github.com/llvm/llvm-project/issues/68404), but I don't think it's a particularly nice solution
let me know what I should change (there's some code duplication that should probably be extracted out)

https://github.com/llvm/llvm-project/pull/69473