Proxying Ranger UI does not work with Ranger-KnoxSSO

When Proxying the Ranger UI and turning on SSO for Ranger, the rewrite rule for the Location header in the Ranger UI service messes with the redirect meant for the SSO.

The fix would be to make the rule more specific in the Ranger UI service. Since the only redirect here is for the login page, we can match the rewrite to login page specifically.