### 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
"creating_primaries",
                        primaries.unassigned_new,
                        "restarting_primaries",
                        primaries.unassigned_restarting,
                        "started_primaries",
                        primaries.started + primaries.relocating,
                        "unassigned_replicas",
                        replicas.unassigned,
                        "initializing_replicas",
                        replicas.initializing,
                        "restarting_replicas",
                        replicas.unassigned_restarting,
                        "started_replicas",
                        replicas.started + replicas.relocating
                    )
                );
            } else {
                return HealthIndicatorDetails.EMPTY;
            }
        }
        public List<HealthIndicatorImpact> getImpacts() {
            final List<HealthIndicatorImpact> impacts = new ArrayList<>();
            if (primaries.indicesWithUnavailableShards.isEmpty() == false) {
                String impactDescription = String.format(
                    Locale.ROOT,
                    "Cannot add data to %d %s [%s]. Searches might return incomplete results.",
                    primaries.indicesWithUnavailableShards.size(),
                    primaries.indicesWithUnavailableShards.size() == 1 ? "index" : "indices",
                    getTruncatedIndices(primaries.indicesWithUnavailableShards, clusterMetadata)
                );