### Elasticsearch Version

8.4, 8.5, 8.6

### Installed Plugins

_No response_

### Java Version

_bundled_

### OS Version

Darwin

### Problem Description

The shards availability indicator should always be reporting diagnosis when its status is RED/YELLOW.
However, when an index is on a data node that runs out of disk space it will report RED but no diagnosis.

### Steps to Reproduce

Have multi-node cluster where a data (non-master) node that hosts an index runs out of disk space (the index cannot relocate somewhere else).
Call the Health API and the output will be something along these lines:
```
    "shards_availability": {
      "status": "red",
      "symptom": "This cluster has all shards available.",
      "details": {
        "initializing_primaries": 1,
        "started_replicas": 0,
        "initializing_replicas": 0,
        "unassigned_primaries": 0,
        "started_primaries": 1,
        "creating_primaries": 0,
        "unassigned_replicas": 0,
        "restarting_primaries": 0,
        "restarting_replicas": 0
      },
      "impacts": [
        {
          "id": "elasticsearch:health:shards_availability:impact:primary_unassigned",
          "severity": 1,
          "description": "Cannot add data to 1 index [test_index]. Searches might return incomplete results.",
          "impact_areas": [
            "ingest",
            "search"
          ]
        }
      ] 
    }
``` 

### Logs (if relevant)

_No response_
server/src/test/java/org/elasticsearch/cluster/routing/allocation/ShardsAvailabilityHealthIndicatorServiceTests.java
.build();
                indexMetadataBuilder.settings(settings);
                indexMetadataList.add(indexMetadataBuilder.build());
            }
        }
        return indexMetadataList;
    }
    private static ClusterState createClusterStateWith(
        List<IndexMetadata> indexMetadataList,
        List<IndexRoutingTable> indexRoutingTables,
        List<NodeShutdown> nodeShutdowns,
        List<DiscoveryNode> nodes
    ) {
        var routingTableBuilder = RoutingTable.builder();
        for (IndexRoutingTable indexRoutingTable : indexRoutingTables) {
            routingTableBuilder.add(indexRoutingTable);
        }
        var nodesShutdownMetadata = new NodesShutdownMetadata(
            nodeShutdowns.stream()
                .collect(
                    toMap(
                        it -> it.nodeId,
                        it -> SingleNodeShutdownMetadata.builder()
                            .setNodeId(it.nodeId)
                            .setType(it.type)
                            .setReason("test")
                            .setNodeSeen(true)
                            .setStartedAtMillis(System.currentTimeMillis())
                            .setAllocationDelay(it.allocationDelaySeconds != null ? timeValueSeconds(it.allocationDelaySeconds) : null)
                            .build()