Added tests for validating enemy sprite ranges

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

apps/wolf_3d_gui/lib/screens/sprite_gallery.dart

@@ -59,7 +59,10 @@ class SpriteGallery extends StatelessWidget {
                   textAlign: TextAlign.center,
                 ),
                 Expanded(
-                  child: WolfAssetPainter.sprite(sprites[index]),
+                  child: AspectRatio(
+                    aspectRatio: 4 / 3,
+                    child: WolfAssetPainter.sprite(sprites[index]),
+                  ),
                 ),
               ],
             ),