server/application_api: TestAdminAPINonTableStats does not work with secondary tenants

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:
```

**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