refactor[react-devtools]: flatten reload and profile config (#31132)

Stacked on https://github.com/facebook/react/pull/31131. See last
commit.

This is a clean-up and a pre-requisite for next changes:
1. `ReloadAndProfileConfig` is now split into boolean value and settings
object. This is mainly because I will add one more setting soon, and
also because settings might be persisted for a longer time than the flag
which signals if the Backend was reloaded for profiling. Ideally, this
settings should probably be moved to the global Hook object, same as we
did for console patching.
2. Host is now responsible for reseting the cached values, Backend will
execute provided `onReloadAndProfileFlagsReset` callback.