[sr1k3sh]

Fixes #539

Problem
NavModule is a process-wide singleton (allocWithZone + dispatch_once) that outlives the React Native instance. On a reload (CMD+R, fast refresh) nothing detaches it from the navigator / road-snapped location provider, so the next navigator callback emits through the event emitter of the torn-down runtime and the app aborts.

Reproduced on main (v0.18.0), example app, iPhone 16 Pro simulator (iOS 18.6): start guidance + route simulation, then reload:

-[GMSNavigator routeProgressMonitor:didUpdateRemainingTime:]
  -[NavModule navigator:didUpdateRemainingTime:]
    -[NavModule onRemainingTimeOrDistanceChangedWithNavigator:]
      -[NativeNavModuleSpecBase emitOnRemainingTimeOrDistanceChanged:]
        NativeNavModuleSpecJSI … unordered_map<…IAsyncEventEmitter> insert
          → std::__throw_overflow_error → abort (SIGABRT)

Fix

• Implement invalidate (called by React Native on reload) to remove the navigator and road-snapped location listeners and drop the event emitter, on the main queue.
• Skip emitting in the INavigationCallback methods while no emitter is set (same check NavAutoModule already uses).
• On the next initialization, initializeSession re-adds the listeners and setEventEmitterCallback restores the emitter, so events keep working after a reload.

Testing
Example app, iPhone 16 Pro simulator, iOS 18.6, Navigation SDK 11.1.0:

• Before: reload during simulated guidance crashes (stack above).
• After: 3/3 reloads during active guidance, no crash; after reload, navigation re-initializes, and onStartGuidance / remaining-time updates reach JS again.

Not tested on Android (change is iOS-only).