fix: remove unused imports flagged by Codacy

Union in adaptive_images.py and field in adaptive_layout.py are both
imported but never used -- the last two Codacy findings on this PR,
matching the same fix already applied on PR #396.

src/adaptive_images.py

@@ -25,7 +25,7 @@ uncached primitives.
 """
 
 from dataclasses import dataclass
-from typing import Any, Optional, Tuple, Union
+from typing import Any, Optional, Tuple
 
 from PIL import Image
 

src/adaptive_layout.py

@@ -29,7 +29,7 @@ freetype.Face, so it drops straight into DisplayManager.draw_text().
 
 import logging
 from collections import OrderedDict
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from typing import Any, Dict, List, Optional, Sequence, Tuple, Union
 
 import freetype