Currently all tests which leverage the admin API are not eligible for randomized testing within tenants due to the fact that the admin API isn't accessible within tenants. With plans to unify the architecture such that we're running multi-tenanted environments everywhere, we'll need the admin API to work within tenants (though it may require elevated privileges).

This issue should enable the tests inside admin_test.go such that they can run probabilistically within tenants.

Jira issue: CRDB-15969

Epic CRDB-31933