admin apis: remove usages of TODOTestTenantDisabled

[shubhamdhama]

Tests count (est.): 3

We have identified several instances of TODOTestTenantDisabled in pkg/server/application_api/ that should be investigated and enabled to run in multi-tenant mode.

❯ rg -n TODOTestTenantDisabled -- pkg/server/storage_api/rangelog_test.go pkg/ccl/serverccl/admin_test.go | sort

pkg/ccl/serverccl/admin_test.go:123:            DefaultTestTenant: base.TODOTestTenantDisabled,
pkg/server/storage_api/rangelog_test.go:100:                    DefaultTestTenant: base.TODOTestTenantDisabled,
pkg/server/storage_api/rangelog_test.go:31:             DefaultTestTenant: base.TODOTestTenantDisabled,

❯ rg -l TODOTestTenantDisabled -- pkg/server/storage_api/rangelog_test.go pkg/ccl/serverccl/admin_test.go | sort | uniq | xargs -I {} whoownsit {} | sort

cockroachdb/obs-prs   pkg/ccl/serverccl/admin_test.go
cockroachdb/unowned   pkg/server/storage_api/rangelog_test.go

Informs: #138912
Epic: CRDB-38970

Jira issue: CRDB-48525