Android: Segmentation fault fix, PendingIntent flag, and other fixes (#12960)

* Android: Segmentation fault fix, PendingIntent flag, and other fixes

- Information about the crosshair is sent after camera initialization.
- Since API 31, PendingIntent requires mutability flag.
- super (class) is called in onRequestPermissionsResult().
- GameActivity suppresses "unused" warning since most of its methods are called from native code.
- Non-null safety is added for nullable function calls.
- Warning/error logging is added for various function calls' return value.

* Move utility functions into Utils.java

- Some nullable functions are changed to be non-null functions.
- Some null checking outside it is removed.
- More annotations are added to functions and parameters.

src/client/game.cpp

@@ -1421,7 +1421,6 @@ bool Game::createClient(const GameStartData &start_data)
 	if (g_touchscreengui) {
 		g_touchscreengui->init(texture_src);
 		g_touchscreengui->hide();
-		g_touchscreengui->setUseCrosshair(!isNoCrosshairAllowed());
 	}
 #endif
 	if (!connectToServer(start_data, &could_connect, &connect_aborted))
@@ -1458,6 +1457,11 @@ bool Game::createClient(const GameStartData &start_data)
 	if (client->modsLoaded())
 		client->getScript()->on_camera_ready(camera);
 	client->setCamera(camera);
+#ifdef HAVE_TOUCHSCREENGUI
+	if (g_touchscreengui) {
+		g_touchscreengui->setUseCrosshair(!isNoCrosshairAllowed());
+	}
+#endif
 
 	/* Clouds
 	 */