Debug: Add sprite dump support to NewGRF objects

src/newgrf_object.cpp

@@ -566,3 +566,8 @@ void TriggerObjectAnimation(Object *o, ObjectAnimationTrigger trigger, const Obj
 		TriggerObjectTileAnimation(o, tile, trigger, spec);
 	}
 }
+
+void DumpObjectSpriteGroup(const ObjectSpec *spec, std::function<void(const char *)> print)
+{
+	DumpSpriteGroup(spec->grf_prop.spritegroup[0], std::move(print));
+}