fix(tests)

- Updated `lerobot_dataset.py:add_frame` to take task as key in frame
- Updated `lerobot_dataset.py` to remove robot argument from `create` function of lerobotdataset and lerobotdatasetmetadata and directly take the features
- Update `test_datasets.py` to features from Mock robot
- Update all the usage of `add_frame` in the library
- Update `dataset_factories.py`; had issues with new argument order
- Raise ValueError when no task is provided (in `datasets/utils.py` validate func)

examples/lekiwi/record.py

@@ -51,10 +51,10 @@ while i < NB_CYCLES_CLIENT_CONNECTION:
     action_sent = robot.send_action(action)
     observation = robot.get_observation()
 
-    frame = {**action_sent, **observation}
     task = "Dummy Example Task Dataset"
+    frame = {**action_sent, **observation, "task": task}
 
-    dataset.add_frame(frame, task)
+    dataset.add_frame(frame)
     i += 1
 
 print("Disconnecting Teleop Devices and LeKiwi Client")