Create a universal way to force-enable Fusebox at Buck build time (#43589)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/43589

Changelog: [Internal]

Adds a way of enabling the Fusebox backend in React Native regardless of the corresponding feature flags. This is only supported in the Buck build and not intended for use in OSS.

Reviewed By: huntie

Differential Revision: D55144502

fbshipit-source-id: 116cd30464acfbd3fafc503300f94cb238adeda8

packages/react-native/ReactCommon/jsinspector-modern/InspectorFlags.cpp

@@ -37,10 +37,19 @@ void InspectorFlags::dangerouslyResetFlags() {
 const InspectorFlags::Values& InspectorFlags::loadFlagsAndAssertUnchanged()
     const {
   InspectorFlags::Values newValues = {
-      .enableCxxInspectorPackagerConnection = ReactNativeFeatureFlags::
-          inspectorEnableCxxInspectorPackagerConnection(),
+      .enableCxxInspectorPackagerConnection =
+#ifdef REACT_NATIVE_FORCE_ENABLE_FUSEBOX
+          true,
+#else
+          ReactNativeFeatureFlags::
+              inspectorEnableCxxInspectorPackagerConnection(),
+#endif
       .enableModernCDPRegistry =
+#ifdef REACT_NATIVE_FORCE_ENABLE_FUSEBOX
+          true,
+#else
           ReactNativeFeatureFlags::inspectorEnableModernCDPRegistry(),
+#endif
   };
 
   if (cachedValues_.has_value() && !inconsistentFlagsStateLogged_) {