What happened + What you expected to happen

Ultralytics tuning of YOLO models using ray[tune] stopped working on the 2.10.0 release. Works correctly with <=2.9.3 so we've been forced to pin ray[tune]<=2.9.3 now in ultralytics/ultralytics#9254.

See https://github.com/ultralytics/ultralytics/actions/runs/8383428601/job/22959118875 for CI failure.

Versions / Dependencies

ray[tune]==2.10.0

Reproduction script

pip install 'ultralytics==8.1.30' 'ray[tune]==2.10.0'

from ultralytics import YOLO

# Load a YOLOv8 model
model = YOLO('yolov8n.pt')

# Tune with Ray tune
results = model.tune(use_ray=True)

results in

  File "/usr/local/lib/python3.10/dist-packages/ultralytics/utils/callbacks/raytune.py", line 17, in on_fit_epoch_end
    if ray.tune.is_session_enabled():
AttributeError: module 'ray.tune' has no attribute 'is_session_enabled'

Issue Severity

High: It blocks me from completing my task.