[clang-tidy][NFC] Add option 'RemoveBracesLLVM' to clang-format config (#172755)
We successfully cleared codebase
(https://github.com/llvm/llvm-project/pull/172748,
https://github.com/llvm/llvm-project/pull/172751,
https://github.com/llvm/llvm-project/pull/172752,
https://github.com/llvm/llvm-project/pull/172754) without any
significant issues encountered.
I propose we add `RemoveBracesLLVM: true` which should _drastically_
reduce churn on code reviews.