Improve CasperClientException to include error response "data" field if populated

[meywood]

The "data" field on an invalid request can contain useful information on why an RPC request failed. See the following example:

{"jsonrpc":"2.0","id":"1754083765","error":{"code":-32008,"message":"Invalid Deploy","data":"contract package at ee6cda1c92b1c17b7379139ca7a12bf4df8186ff5df63e65caa94a162cdeae5b does not exist at state root hash 3841399103ddb56fc6f9209a8181140f98c83365446f050b607985225934640a of block 55f6f15de3c4bbb6faf203725c0e29ae605dc676df8f32ee1e292233b2d7cfce at height 3217"}}

if the data field is present if should populate the CasperClientException along with the error message.