[trusted types][www] Add enableTrustedTypesIntegration flag back in (#…

…26016)

## Summary

The flag was first added in #16157 and was rolled out to employees in
D17430095. #25997 removed this flag because it wasn't dynamically set to
a value in www. The www side was mistakenly removed in D41851685 due to
deprecation of a TypedJSModule but we still want to keep this flag, so
let's add it back in + add a GK on the www side to match the previous
rollout.

See D42574435 for the dynamic value change in www

## How did you test this change?

```
yarn test
yarn test --prod
```

packages/shared/forks/ReactFeatureFlags.www-dynamic.js

@@ -51,6 +51,7 @@ export const replayFailedUnitOfWorkWithInvokeGuardedCallback = __DEV__;
 // TODO: These flags are hard-coded to the default values used in open source.
 // Update the tests so that they pass in either mode, then set these
 // to __VARIANT__.
+export const enableTrustedTypesIntegration = false;
 export const disableSchedulerTimeoutBasedOnReactExpirationTime = false;
 export const disableNativeComponentFrames = false;
 // You probably *don't* want to add more hardcoded ones.

packages/shared/forks/ReactFeatureFlags.www.js

@@ -16,6 +16,7 @@ const dynamicFeatureFlags: DynamicFeatureFlags = require('ReactFeatureFlags');
 
 export const {
   disableInputAttributeSyncing,
+  enableTrustedTypesIntegration,
   disableSchedulerTimeoutBasedOnReactExpirationTime,
   warnAboutSpreadingKeyToJSX,
   replayFailedUnitOfWorkWithInvokeGuardedCallback,
@@ -55,7 +56,6 @@ export const enableUseMemoCacheHook = true;
 export const enableUseEffectEventHook = true;
 export const enableHostSingletons = true;
 export const enableClientRenderFallbackOnTextMismatch = false;
-export const enableTrustedTypesIntegration = false;
 
 // Logs additional User Timing API marks for use with an experimental profiling tool.
 export const enableSchedulingProfiler: boolean =