stop render consent screen when user is not logged-in

[nov]

current doorkeeper-openid_connect implementation always renders consent screen when prompt=consent is requested. however, user can be non-authenticated status when requesting. in that case, application tend to redirect to login page, and it conflicts with rendering consent screen, and results in AbstractController::DoubleRenderError error.

this pull request stop rendering consent screen when user is not authenticated, and will render consent screen after the user is authenticated.

[nov]

ok, added changelog.

[nbulaj]

Thanks!