Extract shared GlobalStateObserver from FuseboxSessionObserver (#55485)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/55485

The FuseboxSessionObserver pattern (a native global object with boolean state, subscribers Set, and state change callback) is going to be reused for PerformanceTracerObserver in D92527815. This diff extracts the shared logic into reusable components:

JS: GlobalStateObserver class parameterized by global name and status property.
C++: installGlobalStateObserver() and emitGlobalStateObserverChange() functions parameterized by global name, status property, and callback name.

FuseboxSessionObserver and RuntimeTargetDebuggerSessionObserver now delegate to the shared implementations. No behavior change.

Changelog: [GENERAL] [CHANGED] - extracting shared logic for fuseboxSessionObserver into reusable components

Reviewed By: hoxyq

Differential Revision: D92720212

fbshipit-source-id: 55636943e6870406e8da37789bc508dcc7b40d4b