fix(core): Gate dispatched route name extraction behind useDispatchedActionData

Ensure getRouteNameFromAction is only called when useDispatchedActionData
is enabled. Previously, the route name was extracted from the action
payload even when the feature was disabled, which could change the span
name and beforeStartSpan input for users who hadn't opted in.

Author: alwx

packages/core/src/js/tracing/reactnavigation.ts

@@ -378,7 +378,7 @@ export const reactNavigationIntegration = ({
     }
 
     // Extract route name from dispatch action payload when available
-    const dispatchedRouteName = getRouteNameFromAction(event);
+    const dispatchedRouteName = useDispatchedActionData ? getRouteNameFromAction(event) : undefined;
     if (useDispatchedActionData && !dispatchedRouteName && !isAppRestart) {
       debug.log(`${INTEGRATION_NAME} Navigation action has no route name in payload, not starting navigation span.`);
       return;