### 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
SnapshotShardSizeInfo.EMPTY,
            System.nanoTime()
        );
        allocation.setDebugMode(RoutingAllocation.DebugMode.ON);
        ShardAllocationDecision shardAllocationDecision = allocationService.explainShardAllocation(shardRouting, allocation);
        AllocateUnassignedDecision allocateDecision = shardAllocationDecision.getAllocateDecision();
        if (LOGGER.isTraceEnabled()) {
            if (allocateDecision.isDecisionTaken()) {
                LOGGER.trace("[{}]: Allocation decision [{}]", shardRouting.shardId(), allocateDecision.getAllocationDecision());
            } else {
                LOGGER.trace("[{}]: Decision taken [false]", shardRouting.shardId());
            }
        }
        if (allocateDecision.isDecisionTaken() && AllocationDecision.NO == allocateDecision.getAllocationDecision()) {
            if (LOGGER.isTraceEnabled()) {
                LOGGER.trace(
                    "[{}]: Working with decisions: [{}]",
                    shardRouting.shardId(),
                    allocateDecision.getNodeDecisions()
                        .stream()
                        .map(
                            n -> n.getCanAllocateDecision()
                                .getDecisions()
                                .stream()
                                .map(d -> d.label() + ": " + d.type())
                                .collect(Collectors.toList())
                        )
                        .collect(Collectors.toList())
                );
            }