Fixed missing brackets in tensorboard summary.py (#6960)

python/open3d/visualization/tensorboard_plugin/summary.py

@@ -424,7 +424,7 @@ def get_or_check_shape(prop, tensor_tuple, exp_shape):
  raise ValueError(
  f"Property {prop} tensor should have shape[{k}]"
  f"={s} for all elements but is "
- f"{tensor.shape[k-1] for tensor in tensor_tuple}.")
+ f"{[tensor.shape[k-1] for tensor in tensor_tuple]}.")
 
  return shape[:2]