HOTFix : Training Instance in Notification

[kshitijrajsharma]

What does this PR do ?

• This PR adds new field in the usernotification table called training
• API response is updated to include training_model so that it can be used to create onclick on frontend
• Also adds notification when user cancels the training

Example response :

    {
      "id": 91,
      "is_read": false,
      "created_at": "2025-03-18T15:19:47.780417Z",
      "read_at": null,
      "message": "Training 959 has Failed.",
      "training_model": 50
    }

How to test ?

• Just hit /notifications/me you would see the new training_model field