Fix member role preloaders when IDs are passed instead of objects

What does this MR do and why?

• Fix member role preloaders when IDs are passed instead of objects

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

How to set up and validate locally

1. Turn on SaaS mode:

export GITLAB_SIMULATE_SAAS=1

2. In the rails console, run:

user = User.first

project_ids = user.authorized_projects.pluck_primary_key
::Authz::Project.new(user, scope: project_ids).permitted

group_ids = user.authorized_groups.pluck_primary_key
::Authz::Group.new(user, scope: group_ids).permitted

Related to #513210