[Multi-Tenant] Allow viewing deleted tenants

[mkurapov]

Context

Currently, if a tenant is deleted, it is not possible to fetch it using the tenant query.
However, this doesn't play nicely with the Admin UI: you are unable to navigate to the tenant details screen from the tenant list page.

If you are the operator tenant, we should allow fetching deleted tenants, and being able to view details.

Todos

• Allow the tenant Admin API resolver to return deleted tenants if an operator is making the request.
• Allow clicking into tenant details in the Admin UI for deleted tenants. The fields should not be editable.

PR:

#3299

[mkurapov]

• Blocked by [Multi-Tenant] Tenant List, Create and Edit Admin UI Pages #2915

[koekiebox]

View for an active tenant:

View only for a deleted tenant: