Ensure ReactFeatureFlag fields are not deleted by Redex

Summary:
Since we are now using ReactFeatureFlag from C++, we need to ensure redex doesn't strip its fields.

changelog: [internal] internal

Reviewed By: JoshuaGross

Differential Revision: D28360678

fbshipit-source-id: 74604e2d008a056c161d8b6ab8f5b30807087d9e

ReactAndroid/src/main/java/com/facebook/react/config/BUCK

@@ -1,4 +1,4 @@
-load("//tools/build_defs/oss:rn_defs.bzl", "rn_android_library")
+load("//tools/build_defs/oss:rn_defs.bzl", "react_native_dep", "rn_android_library")
 
 rn_android_library(
     name = "config",
@@ -9,5 +9,6 @@ rn_android_library(
         "PUBLIC",
     ],
     deps = [
+        react_native_dep("java/com/facebook/proguard/annotations:annotations"),
     ],
 )

ReactAndroid/src/main/java/com/facebook/react/config/ReactFeatureFlags.java

@@ -7,6 +7,8 @@
 
 package com.facebook.react.config;
 
+import com.facebook.proguard.annotations.DoNotStripAny;
+
 /**
  * Hi there, traveller! This configuration class is not meant to be used by end-users of RN. It
  * contains mainly flags for features that are either under active development and not ready for
@@ -14,6 +16,7 @@ package com.facebook.react.config;
  *
  * <p>These values are safe defaults and should not require manual changes.
  */
+@DoNotStripAny
 public class ReactFeatureFlags {
 
   /**
@@ -33,9 +36,7 @@ public class ReactFeatureFlags {
   /** Should we dispatch TurboModule methods with promise returns to the NativeModules thread? */
   public static volatile boolean enableTurboModulePromiseAsyncDispatch = false;
 
-  /*
-   * This feature flag enables logs for Fabric
-   */
+  /** This feature flag enables logs for Fabric */
   public static boolean enableFabricLogs = false;
 
   /**