Include the `godot_plugin_jni.cpp` file into the `platform/android/SCsub` file

This should resolve https://github.com/godotengine/godot/issues/57209

platform/android/SCsub

@@ -18,6 +18,7 @@ android_files = [
     "jni_utils.cpp",
     "android_keys_utils.cpp",
     "display_server_android.cpp",
+    "plugin/godot_plugin_jni.cpp",
     "vulkan/vulkan_context_android.cpp",
 ]
 

platform/android/plugin/godot_plugin_jni.cpp

@@ -126,7 +126,7 @@ JNIEXPORT void JNICALL Java_org_godotengine_godot_plugin_GodotPlugin_nativeEmitS
 		env->DeleteLocalRef(j_param);
 	};
 
-	singleton->emit_signal(SNAME(signal_name), args, count);
+	singleton->emit_signal(StringName(signal_name), args, count);
 }
 
 JNIEXPORT void JNICALL Java_org_godotengine_godot_plugin_GodotPlugin_nativeRegisterGDNativeLibraries(JNIEnv *env, jclass clazz, jobjectArray gdnlib_paths) {