Enable GUI Visualization on Docker with X11 Forwarding (#11729)

Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>
Co-authored-by: Gereziher Adhane <gereziherw@gmail.com>
Co-authored-by: Francesco Mattioli <Francesco.mttl@gmail.com>
Co-authored-by: Burhan <62214284+Burhan-Q@users.noreply.github.com>

ultralytics/utils/checks.py

@@ -535,7 +535,8 @@ def check_imshow(warn=False):
     """Check if environment supports image displays."""
     try:
         if LINUX:
-            assert "DISPLAY" in os.environ and not IS_DOCKER and not IS_COLAB and not IS_KAGGLE
+            assert not IS_COLAB and not IS_KAGGLE
+            assert "DISPLAY" in os.environ, "The DISPLAY environment variable isn't set."
         cv2.imshow("test", np.zeros((8, 8, 3), dtype=np.uint8))  # show a small 8-pixel image
         cv2.waitKey(1)
         cv2.destroyAllWindows()