Show all access levels in the Custom roles UI

What does this MR do and why?

It fixes the UI of custom roles. Now we show guest, reporter, developer and maintainer as base access role.

I skipped owner as they should have all permissions.

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Enable this feature flag: echo "Feature.enable(:custom_roles_ui_self_managed)" | gdk rails console
2. Enable the Ultimate license in one of the groups. This is done going to /admin/groups select Edit on a top level group, and choose the Ultimate plan. For example, /admin/groups/flightjs/edit
3. Go to /admin/application_settings/roles_and_permissions, select the Ultimate group and start creating a custom role
4. Check that you can see roles mentioned in the beginning of this description in the "Base role to use as template"

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #425844 (closed)