Return proper error message in PATCH /orgs/{orgid}/users/{username} when no valid attributes are specified

[ewee33]

In this route, a check is done to see if no valid attributes were specified. If so, it attempts to return code 400 BAD INPUT with an associated error message. However, there are two problems:

• The return statement is improperly formatted, causing no return to actually occur and execution of the route to continue.
• The error message provided is incorrect, referencing an agbot rather than a user