These run against a stub OAuth server implementation, verifying that we
are able to run an end-to-end login transaction for both the authorization
code and the password grant types.
This includes adding support for authorization code grants to our stub
OAuth server implementation; it previously supported only the password
grant type.
One of the show json command tests expected no error when presented with
an invalid configuration in a nested module. Modify the test created in
PR #21569 so that it can still verify there is no panic, but now expect
an error from init.