Change fixtures to managed roles to work with expected validators

[AlanCoding]

This is an enabling PR to fix downstream test failures so we can clear the way for https://github.com/ansible/django-ansible-base/pull/562, which changes the default behavior so you can't create custom roles with non-read permissions to shared resources.

The org_admin_rd role was returning effectively a custom role, but we really don't want to allow creating this sort of custom roles.

[sonarcloud[bot]]

Quality Gate passed

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0 New issues
0 Accepted issues

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0.0% Coverage on New Code
0.0% Duplication on New Code

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