Is your feature request related to a problem? Please describe.

A number of Connector methods need to be accessed during SQL server startup. We need to ensure that all of them can be served without leaving the local region. This will likely require making some of the relevant system tables LOCALITY GLOBAL (#63365).

Below find an incomplete list:

• system.tenant_settings
• system.tenants

Describe alternatives you've considered

As is often the case, we could use stale reads and think more.

Additional context
Relates to #85612

Epic: CRDB-18596

Jira issue: CRDB-18413