Fix trailing whitespace in test_custom.py

Co-authored-by: Kludex <7353520+Kludex@users.noreply.github.com>

Author: Copilot

tests/handlers/test_custom.py

@@ -69,7 +69,7 @@ def test_custom_handler_infer():
     """Test the infer method of CustomHandler."""
     event_with_key = {"my-custom-key": 1}
     event_without_key = {"other-key": 1}
-    
+
     assert CustomHandler.infer(event_with_key, {}, {"api_gateway_base_path": "/"}) is True
     assert CustomHandler.infer(event_without_key, {}, {"api_gateway_base_path": "/"}) is False
 
@@ -78,6 +78,6 @@ def test_custom_handler_call():
     """Test the __call__ method of CustomHandler."""
     event = {"my-custom-key": 1}
     handler = CustomHandler(event, {}, {"api_gateway_base_path": "/"})
-    
+
     result = handler(status=200, headers=[], body=b"Hello, World!")
     assert result == {"statusCode": 200, "headers": {}, "body": "Hello, World!"}