### Description

Elasticsearch defines the concept of a [feature](https://www.elastic.co/guide/en/elasticsearch/reference/current/get-features-api.html) for the purpose of better managing them when snapshotting/restoring them via the [feature_states field](https://www.elastic.co/guide/en/elasticsearch/reference/current/create-snapshot-api.html#create-snapshot-api-feature-states)

The `shards_availability` health indicator currently diagnoses the condition of indices needing to be [restored from a snapshot](https://github.com/elastic/elasticsearch/blob/main/server/src/main/java/org/elasticsearch/cluster/routing/allocation/ShardsAvailabilityHealthIndicatorService.java#L138) and recommends a [troubleshooting guide](http://ela.st/restore-snapshot)

However, since `8.x` the restore API **must** use `feature_states` instead of specifying systems indices or system data streams as part of the `indices` field.

This proposes the `affected_resources` for the `restore_from_snapshot` diagnosis return the indices that are not part of a `feature` under the `INDICES` type, and a new type `FEATURES`.
e.g. instead of current behaviour
```
"affected_resources": {
  "indices": [
    ".geoip_databases",
    "test_index"
    ]
}
```
we could return:
```
"affected_resources": {
  "indices": [
    "test_index"
   ], 
  "features": [
     "geoip"
  ]
}
```



server/src/main/java/org/elasticsearch/node/Node.java
}
            final IngestService ingestService = new IngestService(
                clusterService,
                threadPool,
                this.environment,
                scriptService,
                analysisModule.getAnalysisRegistry(),
                pluginsService.filterPlugins(IngestPlugin.class),
                client
            );
            final SetOnce<RepositoriesService> repositoriesServiceReference = new SetOnce<>();
            final ClusterInfoService clusterInfoService = newClusterInfoService(settings, clusterService, threadPool, client);
            final UsageService usageService = new UsageService();
            SearchModule searchModule = new SearchModule(settings, pluginsService.filterPlugins(SearchPlugin.class));
            IndexSearcher.setMaxClauseCount(SearchUtils.calculateMaxClauseValue(threadPool));
            List<NamedWriteableRegistry.Entry> namedWriteables = Stream.of(
                NetworkModule.getNamedWriteables().stream(),
                IndicesModule.getNamedWriteables().stream(),
                searchModule.getNamedWriteables().stream(),
                pluginsService.flatMap(Plugin::getNamedWriteables),
                ClusterModule.getNamedWriteables().stream(),
                SystemIndexMigrationExecutor.getNamedWriteables().stream()
            ).flatMap(Function.identity()).toList();
            final NamedWriteableRegistry namedWriteableRegistry = new NamedWriteableRegistry(namedWriteables);
            NamedXContentRegistry xContentRegistry = new NamedXContentRegistry(
                Stream.of(
                    NetworkModule.getNamedXContents().stream(),
                    IndicesModule.getNamedXContents().stream(),
                    searchModule.getNamedXContents().stream(),
                    pluginsService.flatMap(Plugin::getNamedXContent),