### Elasticsearch Version

8.8.1+ but probably all versions

### Installed Plugins

_No response_

### Java Version

_bundled_

### OS Version

cloud

### Problem Description

This is a follow-up of [#97370](https://github.com/elastic/elasticsearch/issues/97370). 

In a case where disk spaces are reaching limits, if ILM suddenly tries to move a lot of hot shards to cold/frozen shards, it can tip the cluster health to RED because a lot of cold/frozen shards may be created and stay unassigned as long as there is not enough disk space. However, this is not a suitable indicator for service unavailability, since the data is still safely in the respective hot shards that are becoming cold/frozen, and will remain there until the cold/frozen shards are assigned so that searches can still search them.

Thus the [Health Report API](https://www.elastic.co/guide/en/elasticsearch/reference/8.8/health-api.html) should not return RED for unassigned cold/frozen shards of ILM moves.

### Steps to Reproduce

In a case where disk spaces are reaching limits, if ILM suddenly tries to move a lot of hot shards to cold/frozen shards, it can tip the cluster health to RED because a lot of cold/frozen shards may be created and stay unassigned (as long as there is not enough disk space).

### Logs (if relevant)

_No response_
x-pack/plugin/searchable-snapshots/src/main/java/org/elasticsearch/xpack/searchablesnapshots/SearchableSnapshots.java
new DedicatedFrozenNodeAllocationDecider()
        );
    }
    public List<ExecutorBuilder<?>> getExecutorBuilders(Settings settings) {
        return List.of(executorBuilders(settings));
    }
    public static final String SNAPSHOT_RECOVERY_STATE_FACTORY_KEY = "snapshot_prewarm";
    @Override
    public Map<String, RecoveryStateFactory> getRecoveryStateFactories() {
        return Map.of(SNAPSHOT_RECOVERY_STATE_FACTORY_KEY, SearchableSnapshotRecoveryState::new);
    }
    public static final String CACHE_FETCH_ASYNC_THREAD_POOL_NAME = "searchable_snapshots_cache_fetch_async";
    public static final String CACHE_FETCH_ASYNC_THREAD_POOL_SETTING = "xpack.searchable_snapshots.cache_fetch_async_thread_pool";
    public static final String CACHE_PREWARMING_THREAD_POOL_NAME = "searchable_snapshots_cache_prewarming";
    public static final String CACHE_PREWARMING_THREAD_POOL_SETTING = "xpack.searchable_snapshots.cache_prewarming_thread_pool";
    public static ScalingExecutorBuilder[] executorBuilders(Settings settings) {
        final int processors = EsExecutors.allocatedProcessors(settings);
        
        
        
        final boolean rejectAfterShutdown = true;
        return new ScalingExecutorBuilder[] {
            new ScalingExecutorBuilder(
                CACHE_FETCH_ASYNC_THREAD_POOL_NAME,
                0,
                Math.min(processors * 3, 50),
                TimeValue.timeValueSeconds(30L),
                rejectAfterShutdown,
                CACHE_FETCH_ASYNC_THREAD_POOL_SETTING
            ),