ML backend state not showing TRAINING

[brightns]

Describe the bug When training a model, ML backend state is set to MLBackendState.CONNECTED instead of TRAINING. Not sure if this is expected behavior though.

To Reproduce Steps to reproduce the behavior:

1. Go to /settings/ml
2. Click Start Training
3. Reload page?

Expected behavior ML backend state should be TRAINING

Additional context update_state() does not account for training https://github.com/heartexlabs/label-studio/blob/f4fb29083cec2784839210277b02319ff00cc79c/label_studio/ml/models.py#L103-L115

[jrdalenberg]

Is there any way of making the training state more obvious for a user? I observed users spam clicking the training button because there is no feedback.

Ideas:

• backend status updates ("Training started!" when clicked and "Already training!" when clicking again)
• Greyed out training button until training is finished

And perhaps support progress feedback, such as a progress bar for the training using steps / epochs info.