OIDC stays signed with no permissions if user doesn't have HTTP permissions. We should log out on the login screen

If I have a OIDC user with no HTTP permissions, when login in I get a blank screen with a login button. The first fix we would need would be telling the user they are not seeing anything because they lack HTTP permissions and should contact their admin.

Other than this, when I click on login, I am taken back to the login screen, but if I try login in now with a questdb user, like admin/quest, rather than with OIDC, I get the blank screen again and logs indicate I don't have permissions, even if from my point of view I seem to be logging in with the admin user.

The problem seems to be we don't do a proper logout when we display the login screen, so if the user with no permissions was logged in, we are still trying to use that one. The only two ways I got to get out of this situation (both not ideal) were:

• disable OIDC temporarily on the server, so admin user can log in again
• just grant HTTP to the OIDC user, so we can access web console and click on log out

The web console should do the logout automatically in this case when we detect no HTTP permissions. Also, an error message would be appreciated.

Start by tracing the login screen and the OIDC logout handling in the web console, then reproduce the flow with an OIDC user who lacks HTTP permissions. The change is complete when this case logs the user out automatically, shows an explanatory error, and allows a subsequent QuestDB login.