### 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",
                        unavailableReplicas.size(),
                        "started_replicas",
                        availableReplicas.size()
                    ),
                    List.of(
                        new HealthIndicatorImpact(
                            NAME,
                            ShardsAvailabilityHealthIndicatorService.REPLICA_UNASSIGNED_IMPACT_ID,
                            2,
                            "Searches might be slower than usual. Fewer redundant copies of the data exist on 1 index [yellow-index].",
                            List.of(ImpactArea.SEARCH)
                        )
                    ),
                    List.of(
                        new Diagnosis(ACTION_CHECK_ALLOCATION_EXPLAIN_API, List.of(new Diagnosis.Resource(INDEX, List.of("yellow-index"))))
                    )
                )
            )
        );
    }
    public void testShouldBeRedWhenThereAreUnassignedPrimariesAndUnassignedReplicas() {
        var clusterState = createClusterStateWith(
            List.of(index("red-index", new ShardAllocation(randomNodeId(), UNAVAILABLE), new ShardAllocation(randomNodeId(), UNAVAILABLE))),
            List.of()
        );
        var service = createShardsAvailabilityIndicatorService(clusterState);
        assertThat(
            service.calculate(true, HealthInfo.EMPTY_HEALTH_INFO),
            equalTo(