Update polygon creation offset parameter in drawing.py - fix bug

Replaced grid_size-based scaling with a fixed value of 0.15 for the polygon creation offset. This change ensures consistency in offset scaling regardless of the grid size.

cooperative_cuisine/pygame_2d_vis/drawing.py

@@ -677,7 +677,7 @@ class Visualizer:
             )
         elif "content_list" in item and item["content_list"]:
             triangle_offsets = create_polygon(
-                len(item["content_list"]), np.array([0, self.grid_size * 0.15])
+                len(item["content_list"]), np.array([0, 0.15])
             )
             scale = 1 if len(item["content_list"]) == 1 else 0.6
             for idx, o in enumerate(item["content_list"]):