How to get Username from keycloak

I already create a user in keycloak, its Username is ‘john’ and its email is ‘’, now I try to use this user to login Grafana, it is successful. But check the user’s profile in Grafana, the value in Username textbox is email, so what I actually got was a email address when I used global built-in variable ${__user.login} to get Username in a dashboard.

so how to solve this problem?
the value of scopes I define in [auth.generic_oauth] is ‘scopes = profile email’, How do I change the value of ‘scopes’ or modify the associated configuration in keycloak?