[tempo-distributed] incorrect storageClass in volumeClaimTemplates when using zoneAwareReplication

[shityakov]

Describe the bug
When using zoneAwareReplication with different storageClass values per zone, the storageClassName in volumeClaimTemplates for ingester StatefulSets is not rendered correctly. Instead, it falls back to the global or empty value, ignoring the zone-specific storageClass.

To Reproduce
Use the following values.yaml configuration:

ingester:
  persistence:
    enabled: true
    size: 12Gi
  zoneAwareReplication:
    enabled: true
    topologyKey: topology.kubernetes.io/zone
    zones:
      - name: ru-2a
        nodeSelector:
          topology.kubernetes.io/zone: ru-2a
        storageClass: fast.ru-2a
      - name: ru-2b
        nodeSelector:
          topology.kubernetes.io/zone: ru-2b
        storageClass: fast.ru-2b
      - name: ru-2c
        nodeSelector:
          topology.kubernetes.io/zone: ru-2c
        storageClass: fast.ru-2c

After installing the Helm chart, inspect the StatefulSets for the ingesters. The storageClassName in volumeClaimTemplates does not reflect the zone-specific value (fast.ru-2a, etc.).

Expected behavior
Each StatefulSet corresponding to a zone should use its respective storageClass as defined under zones[].storageClass.

Actual behavior
All StatefulSets either use the global storageClass, a default value, or omit storageClassName entirely.

Environment:

• Tempo chart version: 1.41.1

Additional Context
The tempo-distributed/templates/ingester/statefulset-ingester.yaml template uses a $storageClass, which causes it to ignore per-zone overrides from zoneAwareReplication.zones[].storageClass.

Proposed fix
Use $rolloutZone.storageClass inside volumeClaimTemplates when rendering zone-specific StatefulSets.