improves a utility function logging

[wyli]

Is your feature request related to a problem? Please describe.

MONAI/monai/networks/utils.py

Line 522 in 32af32c

print(f"'dst' model updated: {len(updated_keys)} of {len(dst_dict)} variables.")

the copy_model_state's logging output is often useful for applications built using this component, but printing to stdout is too restrictive.