server/application_api: TestAdminAPINonTableStats does not work with secondary tenants

[knz]

Found while investigating #110001.

Describe the problem

When TestAdminAPINonTableStats is modified to point to a secondary tenant, it starts failing:

    storage_inspection_test.go:63: status: 500 Internal Server Error, content-type: application/json, body: {
          "error": "An internal server error has occurred. Please check your CockroachDB logs for more details.",
          "code": 13,
          "message": "An internal server error has occurred. Please check your CockroachDB logs for more details.",
          "details": [
          ]
        }, error: <nil>

To Reproduce

Start from #110008 and reset the DefaultTestTenant parameter.

Expected behavior

When pointed to a secondary tenant the test should work. (It's possible to create non-table data in a secondary tenant by using a scratch range)

Epic CRDB-38970
Jira issue: CRDB-31219