fix: correct import path for Game, read_efg, and read_nfg to avoid circular import

Author: edwardchalstrey1

src/pygambit/catalog/catalog.py

@@ -2,7 +2,7 @@
 from typing import Literal
 
 # import numpy as np
-from pygambit import Game, read_efg, read_nfg
+from pygambit.gambit import Game, read_efg, read_nfg
 
 _GAMEFILES_DIR = Path(__file__).parent.parent.parent.parent / "contrib/games"