### 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"
  ]
}
```



benchmarks/src/main/java/org/elasticsearch/benchmark/routing/allocation/ShardsAvailabilityHealthIndicatorBenchmark.java
@Warmup(iterations = 10)
@Measurement(iterations = 10)
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.MILLISECONDS)
@State(Scope.Benchmark)
@SuppressWarnings("unused") 
public class ShardsAvailabilityHealthIndicatorBenchmark {
    @Param(
        {
            
            "     10000|        1|        0|    3",
            "     20000|        1|        0|    3",
            "     50000|        1|        0|    3",
            "     100000|       1|        0|    3",
            "     200000|       1|        0|    3",
            "     10000|        1|        1|    3",
            "     20000|        1|        1|    3",
            "     50000|        1|        1|    3",
            "     100000|       1|        1|    3",
            "     200000|       1|        1|    3" }
    )
    public String indicesShardsReplicasNodes = "10|1|0|1";
    private ShardsAvailabilityHealthIndicatorService indicatorService;
    @Setup
    public void setUp() throws Exception {