Correct ‘upload_files_via_method_scp’ expected signature.

The ‘upload_files_via_method_scp’ function is used by callers who expect to supply ‘ssh_config_options’ as a list of strings.

The function incorrectly attempts to treat this as a string with a separator, which fails (because the ‘list’ type has no ‘split’ method).

Instead, we alter the function signature to match the expectation of the caller.