Polish SAML SSO configuration page

Overview

With all feature flags enabled, the current group SAML SSO configuration page looks like this:

This looks a bit messy. We should:

• Group read-only fields together. They look too similar to input fields where the user needs to configure something.
• Clean up the toggles.

Proposal

• Move the input fields to a new "Settings" section. Move this to the bottom of the page.
• Use the toggle slider for the "SSO enforcement" setting as well as the SAML SSO toggle setting.