### 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/main/java/org/elasticsearch/cluster/routing/allocation/ShardsAvailabilityHealthIndicatorService.java
var status = new ShardAllocationStatus(state.getMetadata());
        for (IndexRoutingTable indexShardRouting : state.routingTable()) {
            for (int i = 0; i < indexShardRouting.size(); i++) {
                IndexShardRoutingTable shardRouting = indexShardRouting.shard(i);
                status.addPrimary(shardRouting.primaryShard(), state, shutdown, verbose);
                for (ShardRouting replicaShard : shardRouting.replicaShards()) {
                    status.addReplica(replicaShard, state, shutdown, verbose);
                }
            }
        }
        return createIndicator(
            status.getStatus(),
            status.getSymptom(),
            status.getDetails(verbose),
            status.getImpacts(),
            status.getDiagnosis(verbose, maxAffectedResourcesCount)
        );
    }
    
    public static final String PRIMARY_UNASSIGNED_IMPACT_ID = "primary_unassigned";
    public static final String REPLICA_UNASSIGNED_IMPACT_ID = "replica_unassigned";
    public static final String RESTORE_FROM_SNAPSHOT_ACTION_GUIDE = "https://ela.st/restore-snapshot";
    public static final Diagnosis.Definition ACTION_RESTORE_FROM_SNAPSHOT = new Diagnosis.Definition(
        NAME,
        "restore_from_snapshot",
        "Elasticsearch isn't allowed to allocate some shards because there are no copies of the shards in the cluster. Elasticsearch will "
            + "allocate these shards when nodes holding good copies of the data join the cluster.",
        "If no such node is available, restore these indices from a recent snapshot.",
        RESTORE_FROM_SNAPSHOT_ACTION_GUIDE
    );