Allow campaigns to be fetched as clients, to be consistent with Sprinklr naming

I'm up for a better approach here... I just wanted a consistent interface for making the call to get the workspace mappings. I had to do some hackery here, which should also be cleaned up depending on what we do here: https://github.com/opallabs/Opal/commit/eb564b930a605db331b05dac38d0b26c92a93abc#diff-0222947ad2c0e15dba652a664eaa83edR66