Default hostname provider configured with frontendUrl without tailing slash causes following error.

This does not happen on RH-SSO 7.5 or before.

As the request log shows, keycloak.js is loaded from wrong URL (There should be a slash between "auth" and "js". The URL is built from frontendUrl, but current RH-SSO implementation expects frontendUrl finishes with slash. This is unnesseary breaking change from RH-SSO 7.5 or before.