temporarily disable lazy context propagation (facebook#31403)

disables lazy context propagation in oss to help determine if it is
causing bugs in startTransition. Will reenable after cutting a canary
release with this flag disabled

packages/shared/ReactFeatureFlags.js

@@ -101,7 +101,7 @@ export const enableObjectFiber = false;
 
 export const enableTransitionTracing = false;
 
-export const enableLazyContextPropagation = true;
+export const enableLazyContextPropagation = false;
 
 // Expose unstable useContext for performance testing
 export const enableContextProfiling = false;