Hardcode enableLegacyFBSupport flag (facebook#28701)

Hardcode enableLegacyFBSupport flag

Author: kassens

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

@@ -15,7 +15,6 @@
 
 export const disableIEWorkarounds = __VARIANT__;
 export const enableBigIntSupport = __VARIANT__;
-export const enableLegacyFBSupport = __VARIANT__;
 export const enableUseRefAccessWarning = __VARIANT__;
 export const disableSchedulerTimeoutInWorkLoop = __VARIANT__;
 export const enableLazyContextPropagation = __VARIANT__;

packages/shared/forks/ReactFeatureFlags.www.js

@@ -18,7 +18,6 @@ export const {
   disableIEWorkarounds,
   enableBigIntSupport,
   enableTrustedTypesIntegration,
-  enableLegacyFBSupport,
   enableDebugTracing,
   enableUseRefAccessWarning,
   enableLazyContextPropagation,
@@ -57,6 +56,7 @@ export const enableUseEffectEventHook = true;
 export const enableFilterEmptyStringAttributesDOM = true;
 export const enableAsyncActions = true;
 export const disableInputAttributeSyncing = false;
+export const enableLegacyFBSupport = true;
 
 // Logs additional User Timing API marks for use with an experimental profiling tool.
 export const enableSchedulingProfiler: boolean =