Make login_controller consistent with signup_controller by using Client4.getOAuthRoute (#7033)
Make login_controller consistent with signup_controller by using Client4.getOAuthRoute (#7033)

* Use Client4.getOAuthUrl instead of making the url by hand with getUrl

* Use the correct function name. thanks jwilander

rickbatka/mattermost-webapp,rickbatka/mattermost-webapp,rickbatka/mattermost-webapp,rickbatka/mattermost-webapp