Fix featureflags c++ library loading on Android (#42770)

Summary:
On latest `main`, RN Tester was crashing for me just after loading the JS bundle with `java.lang.UnsatisfiedLinkError: dlopen failed: library "libreactfeatureflagsjni.so" not found`

It seems to be named `featureflagsjni` instead in [here](https://github.com/facebook/react-native/blob/main/packages/react-native/ReactAndroid/src/main/jni/react/featureflags/CMakeLists.txt#L11)

## Changelog:

No changelog needed

Pull Request resolved: https://github.com/facebook/react-native/pull/42770

Test Plan:
```bash
./gradlew :packages:rn-tester:android:app:installHermesDebug -PreactNativeArchitectures=arm64-v8a
```

Then run the app, the app was crashing before the fix, not crashing now

Reviewed By: javache

Differential Revision: D53268873

Pulled By: cortinico

fbshipit-source-id: f098ca12baadab358f72b1c9d5720123248b8e1a

packages/react-native/ReactAndroid/build.gradle.kts

@@ -524,6 +524,7 @@ android {
             "react_render_debug",
             "turbomodulejsijni",
             "runtimeexecutor",
+            "react_featureflagsjni",
             "react_codegen_rncore",
             "react_debug",
             "react_featureflags",
@@ -541,7 +542,6 @@ android {
             "jsi",
             "glog",
             "fabricjni",
-            "featureflagsjni",
             "react_render_mapbuffer",
             "yoga",
             "folly_runtime",

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsCxxInterop.kt

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<7b01e2f777839812437c60503ebe321b>>
+ * @generated SignedSource<<9638eb154fe6e488aebcf20c462f498e>>
  */
 
 /**
@@ -25,7 +25,7 @@ import com.facebook.soloader.SoLoader
 @DoNotStrip
 object ReactNativeFeatureFlagsCxxInterop {
   init {
-    SoLoader.loadLibrary("reactfeatureflagsjni")
+    SoLoader.loadLibrary("react_featureflagsjni")
   }
 
   @DoNotStrip @JvmStatic external fun commonTestFlag(): Boolean

packages/react-native/ReactAndroid/src/main/jni/react/featureflags/CMakeLists.txt

@@ -5,18 +5,18 @@
 
 cmake_minimum_required(VERSION 3.13)
 
-file(GLOB featureflagsjni_SRCS CONFIGURE_DEPENDS *.cpp)
+file(GLOB react_featureflagsjni_SRCS CONFIGURE_DEPENDS *.cpp)
 
 add_library(
-        featureflagsjni
+        react_featureflagsjni
         SHARED
         ${featureflagsjni_SRCS}
 )
 
-target_include_directories(featureflagsjni PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+target_include_directories(react_featureflagsjni PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
 
 target_link_libraries(
-        featureflagsjni
+        react_featureflagsjni
         fb
         fbjni
         react_featureflags
@@ -24,7 +24,7 @@ target_link_libraries(
 )
 
 target_compile_options(
-        featureflagsjni
+        react_featureflagsjni
         PRIVATE
         -DLOG_TAG=\"ReactNative\"
         -fexceptions

packages/react-native/ReactAndroid/src/main/jni/react/newarchdefaults/CMakeLists.txt

@@ -17,7 +17,7 @@ target_include_directories(react_newarchdefaults PUBLIC .)
 target_link_libraries(react_newarchdefaults
         fbjni
         fabricjni
-        featureflagsjni
+        react_featureflagsjni
         react_nativemodule_core
         react_codegen_rncore
         react_cxxreactpackage

packages/react-native/ReactAndroid/src/main/jni/react/runtime/jni/CMakeLists.txt

@@ -23,7 +23,7 @@ target_include_directories(rninstance PUBLIC .)
 target_link_libraries(
         rninstance
         fabricjni
-        featureflagsjni
+        react_featureflagsjni
         turbomodulejsijni
         fb
         jsi

packages/react-native/ReactCommon/react/runtime/CMakeLists.txt

@@ -30,7 +30,7 @@ target_link_libraries(
         bridgeless
         jserrorhandler
         fabricjni
-        featureflagsjni
+        react_featureflagsjni
         turbomodulejsijni
         fb
         jsi

packages/react-native/scripts/featureflags/templates/android/ReactNativeFeatureFlagsCxxInterop.kt-template.js

@@ -35,7 +35,7 @@ import com.facebook.soloader.SoLoader
 @DoNotStrip
 object ReactNativeFeatureFlagsCxxInterop {
   init {
-    SoLoader.loadLibrary("reactfeatureflagsjni")
+    SoLoader.loadLibrary("react_featureflagsjni")
   }
 
 ${Object.entries(config.common)