HPCC-11840 Remote Copy "Requires" Credentials

Credentials should not be mandatory as remote environment may have not
have credentials configured.

Fixes HPCC-11840

Signed-off-by: Gordon Smith <gordon.smith@lexisnexis.com>
Merge pull request #6396 from GordonSmith/HPCC-11840

HPCC-11840 Remote Copy "Requires" Credentials

Reviewed-By: Miguel Vazquez <miguel.vazquez@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>