DDP, Comet, URLError fixes, improved error handling (#658)

Co-authored-by: Ayush Chaurasia <ayush.chaurarsia@gmail.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Tungway1990 <68179274+Tungway1990@users.noreply.github.com>

ultralytics/yolo/utils/callbacks/clearml.py

@@ -6,7 +6,7 @@ try:
     import clearml
     from clearml import Task
 
-    assert hasattr(clearml, '__version__')
+    assert clearml.__version__  # verify package is not directory
 except (ImportError, AssertionError):
     clearml = None