Add SoLoaderLibrary annotation stub for Gradle builds (facebook#55859)

Summary:
Pull Request resolved: facebook#55859

changelog: [internal] internal

Reviewed By: fkgozali

Differential Revision: D94950035

fbshipit-source-id: 2b40364646ea2656dc073bb7bc79d3165e953ee4

Author: mdvacca

packages/react-native/ReactAndroid/src/main/java/com/facebook/soloader/annotation/SoLoaderLibrary.kt

@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.facebook.soloader.annotation
+
+/**
+ * Stub annotation for open-source Gradle builds. The real implementation lives in
+ * fbandroid/java/com/facebook/soloader/annotation/ and is used by the internal Buck build for
+ * compile-time validation of native library merging.
+ */
+@Retention(AnnotationRetention.SOURCE)
+@Target(AnnotationTarget.CLASS)
+internal annotation class SoLoaderLibrary(vararg val value: String)