Remove exception throwing from clients

[pc9795]

Ref:

Throwing errors.
We typically return a model from the submission client to give the status (again not required), we do this because we don't want to throw exceptions that might go unhandled. Our goals in the client is to never blow up a clients application ever, just log out a failure happened. Would be good to ensure we are ensuring the exceptions we do throw are caught at the call sites.