`DatabaseConfiguration::maxZoneFailuresTolerated` should account for redundancy mode when computing availability

If a cluster is running in `three_data_hall` mode, on three data halls, there is a case where losing a single zone will cause unavailability due to stuck recovery, even though in status, we see:

```
$ fdbcli --exec 'status json' | jq .cluster.fault_tolerance.max_zone_failures_without_losing_availability
2
```

The redundancy mode should be used in the availability calculation, to avoid confusing status output.

Start by tracing DatabaseConfiguration::maxZoneFailuresTolerated and the status JSON fault-tolerance calculation. Reproduce or inspect the three_data_hall case with three data halls and compare the reported value with the stuck-recovery availability behavior. Done means status no longer reports availability that conflicts with the redundancy mode.

Written by the indexing model from the issue text.