Shorten module paths with new 'nn' dir (#96)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

ultralytics/tests/data/dataloader/yolodetection.py

@@ -1,6 +1,5 @@
 import cv2
 import hydra
-import numpy as np
 
 from ultralytics.yolo.data import build_dataloader
 from ultralytics.yolo.utils import ROOT

ultralytics/tests/functional/test_loaders.py

@@ -1,5 +1,5 @@
+from ultralytics.nn.tasks import DetectionModel
 from ultralytics.yolo.utils.checks import check_yaml
-from ultralytics.yolo.utils.modeling.tasks import DetectionModel
 
 
 def test_model_parser():