### 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
"unassigned_replicas",
            override.getOrDefault("unassigned_replicas", 0),
            "initializing_replicas",
            override.getOrDefault("initializing_replicas", 0),
            "restarting_replicas",
            override.getOrDefault("restarting_replicas", 0),
            "started_replicas",
            override.getOrDefault("started_replicas", 0)
        );
    }
    private static IndexRoutingTable index(String name, ShardAllocation primaryState, ShardAllocation... replicaStates) {
        return index(
            IndexMetadata.builder(name)
                .settings(Settings.builder().put(IndexMetadata.SETTING_VERSION_CREATED, Version.CURRENT).build())
                .numberOfShards(1)
                .numberOfReplicas(replicaStates.length)
                .build(),
            primaryState,
            replicaStates
        );
    }
    private static IndexRoutingTable index(IndexMetadata indexMetadata, ShardAllocation primaryState, ShardAllocation... replicaStates) {
        var index = indexMetadata.getIndex();
        var shardId = new ShardId(index, 0);
        var builder = IndexRoutingTable.builder(index);
        builder.addShard(createShardRouting(shardId, true, primaryState));
        for (var replicaState : replicaStates) {
            builder.addShard(createShardRouting(shardId, false, replicaState));
        }
        return builder.build();