As the Swagger specification indicates, whether the properties inside a
model are required or not must be defined inside a separate "required"
field at the root of the model.
For fields like "parameters", that has to be specified inside each
parameter's key.
The error message under "Unexpected errors" was not the format we
received for any errors. We changed it to be msg and result to fit
with the results we got when for standard Zulip JSON errors.