sql: add observability into span and zone configs.

**Is your feature request related to a problem? Please describe.**
In different escalations we have had customers report confusion where the resulting replica placement was not what they expected. In one case the table zone config was set, but was overridden by a partition config.

**Describe the solution you'd like**
In the UI : reports/range/<#rangeid> we could add what the computed span config is and also which zone config ended up causing this span config to be the "winner". Without this it is hard for a customer to track this down themselves.

**Describe alternatives you've considered**
Better documentation will help as well as other tooling which helps a user find this themselves.

Jira issue: CRDB-33475

Epic CRDB-2245