[React Native] Set allowConcurrentByDefault = true (#21491)

Author: rickhanlonii

packages/shared/forks/ReactFeatureFlags.native-fb.js

@@ -60,7 +60,7 @@ export const enableRecursiveCommitTraversal = false;
 export const disableSchedulerTimeoutInWorkLoop = false;
 export const enableLazyContextPropagation = false;
 export const enableSyncDefaultUpdates = false;
-export const allowConcurrentByDefault = false;
+export const allowConcurrentByDefault = true;
 
 // Flow magic to verify the exports of this file match the original version.
 // eslint-disable-next-line no-unused-vars

packages/shared/forks/ReactFeatureFlags.test-renderer.native.js

@@ -59,7 +59,7 @@ export const enableRecursiveCommitTraversal = false;
 export const disableSchedulerTimeoutInWorkLoop = false;
 export const enableLazyContextPropagation = false;
 export const enableSyncDefaultUpdates = false;
-export const allowConcurrentByDefault = false;
+export const allowConcurrentByDefault = true;
 
 // Flow magic to verify the exports of this file match the original version.
 // eslint-disable-next-line no-unused-vars