Avoid using std::unique_ptr with incomplete type

Summary:
It's not supported, and building with libc++ using its unstable ABI
exposes the issue. Include the header to get the complete type.

Changelog: [Internal]

Reviewed By: lanza, sammy-SC

Differential Revision: D28405500

fbshipit-source-id: 65e039a465d8d736eaecb89e82895889fd2379ca

ReactAndroid/src/main/jni/react/jni/ProxyExecutor.h

@@ -8,6 +8,7 @@
 #pragma once
 
 #include <cxxreact/JSExecutor.h>
+#include <cxxreact/RAMBundleRegistry.h>
 #include <fbjni/fbjni.h>
 #include <jni.h>
 #include "OnLoad.h"