Velaux using dex get token issue

[oleksiybozhyk]

Describe the bug
We have been trying to generate a new access token to use VelaUX Open Apis (previosly we have enabled a dex plugin to have SSO with GitLab), as explained in https://kubevela.io/docs/platform-engineers/openapi/overview/ but when we were trying to get the token the system returned "the login request is invalid" so we have switched attention to dex, which is now the main login meccanism,
by following the apis there is a "handle login request" method that should provide an access token that later should be used for executing requests (https://kubevela.stoplight.io/docs/kubevela/bf08aed77a773-handle-login-request), but this API also require code what is that code?, there are already username and password.

Can you help please to undestand what is the correct way to get the access token to work with Vela APi?

KubeVela Version - v1.9.3
Kubernetes Version - 1.27