In `facet-cut` command, if user does not wish to call an initializer, CLI raises error about lack of initializer calldata

[zomglings]

Just leaving out --initializer-address raises an error incorrectly because for contract initializers that take arguments, the CLI requests --initializer-args to be nonempty even if --initializer-address has not been specified.

We should make it so that the initializer calldata is only populated if the initializer_address is neither None nor the 0 address.

This fix needs to be applied in core.py.