refactor(cameras): width, fps and height is mandatory to have a value in robot config

tests/cameras/test_opencv.py

@@ -28,6 +28,8 @@ from lerobot.common.cameras.configs import Cv2Rotation
 from lerobot.common.cameras.opencv import OpenCVCamera, OpenCVCameraConfig
 from lerobot.common.errors import DeviceAlreadyConnectedError, DeviceNotConnectedError
 
+# NOTE(Steven): Consider improving the assert coverage
+
 
 def test_base_class_implementation():
     config = OpenCVCameraConfig(index_or_path=0)