Improving scribbles fetch data function

[masadcv]

In the current implementation data from dictionary is fetched in scribbles flow using helper function from: https://github.com/Project-MONAI/MONAILabel/blob/main/monailabel/scribbles/transforms.py#L42

While this has not caused any issues currently, the function is really returning a reference to the data object and hence may result in undesirable effects if the reference object is modified by calling function.

To address, this needs to copy data to avoid any unintentional logical error.