Code cleanup for save state notification, add metadata field

UI/NativeApp.cpp

@@ -133,6 +133,7 @@
 #include "UI/OnScreenDisplay.h"
 #include "UI/RemoteISOScreen.h"
 #include "UI/Theme.h"
+#include "UI/PauseScreen.h"
 #include "UI/UIAtlas.h"
 
 #if PPSSPP_PLATFORM(UWP)
@@ -693,12 +694,7 @@ void NativeInit(int argc, const char *argv[], const char *savegame_dir, const ch
 	g_BackgroundAudio.SFX().Init();
 
 	if (!boot_filename.empty() && stateToLoad.Valid()) {
-		SaveState::Load(stateToLoad, -1, [](SaveState::Status status, std::string_view message) {
-			if (!message.empty() && (!g_Config.bDumpFrames || !g_Config.bDumpVideoOutput)) {
-				g_OSD.Show(status == SaveState::Status::SUCCESS ? OSDType::MESSAGE_SUCCESS : OSDType::MESSAGE_ERROR,
-					message, status == SaveState::Status::SUCCESS ? 2.0 : 5.0);
-			}
-		});
+		SaveState::Load(stateToLoad, -1, &ShowMessageAfterSaveStateAction);
 	}
 
 	if (g_Config.bAchievementsEnable) {