Describe the problem

In #74612 we made it so that the tenant has access to its own zone configs via the SystemConfig object provided by the systemconfigwatcher. Unfortunately this did not go far enough to actually fully address #70558 because of this special case logic:

Solution

We need to either remove the above logic or make it conditional on where the config is coming from and more generally make sure that the SystemConfig methods work for the tenant.

Epic: CRDB-10489

Jira issue: CRDB-12864