[llvm] Make llvm::telemetry::Manager::preDispatch protected. (PR #127114)

[Kazu Hirata via llvm-commits]

kazutakahirata wrote:

@oontvoo I've reverted your PR.  I'm happy to test your new version.  By the way, I've locally reproduced the failure with `-DLLVM_ENABLE_WERROR=On` and clang as the host compiler.

https://github.com/llvm/llvm-project/pull/127114