oauth2: Client secret error message should be shown on creation

[aeneasr]

Super Trivial issue, I noticed that when trying to create a test client via commandline, I made the client secret only 5 chars. I get the following very weird response in the command window "Could not validate token: invalid character '{' after top-level value" the logs for hydra fortunately had {"code":500,"details":[],"error":"The client secret must be at least 6 characters long","level":"error","msg": so it was easy to track down. I am running v.0.10.0-alpha18, I'm wondering if more recent versions give a better error message for this case