### CI Link

https://gradle-enterprise.elastic.co/s/dvtf7swsnm44o

### Repro line

./gradlew ':x-pack:plugin:autoscaling:test' --tests "org.elasticsearch.xpack.autoscaling.capacity.AutoscalingCalculateCapacityServiceTests.testContext" -Dtests.seed=15E8E10F966ECA7A -Dtests.locale=be-BY -Dtests.timezone=America/Noronha -Druntime.java=17	

### Does it reproduce?

Yes

### Applicable branches

main

### Failure history

https://gradle-enterprise.elastic.co/scans/tests?search.timeZoneId=Europe/Rome&tests.container=org.elasticsearch.xpack.autoscaling.capacity.AutoscalingCalculateCapacityServiceTests&tests.test=testContext

### Failure excerpt

```
org.elasticsearch.xpack.autoscaling.capacity.AutoscalingCalculateCapacityServiceTests > testContext FAILED
    java.lang.NullPointerException: Cannot invoke "org.elasticsearch.xpack.autoscaling.capacity.AutoscalingCapacity.node()" because the return value of "org.elasticsearch.xpack.autoscaling.capacity.AutoscalingDeciderContext.currentCapacity()" is null
        at __randomizedtesting.SeedInfo.seed([EB0EF2643F2D6C41:7D3B02C92A094B8F]:0)
        at org.elasticsearch.xpack.autoscaling.capacity.AutoscalingCalculateCapacityServiceTests.testContext(AutoscalingCalculateCapacityServiceTests.java:225)
```
x-pack/plugin/autoscaling/src/test/java/org/elasticsearch/xpack/autoscaling/capacity/AutoscalingCalculateCapacityServiceTests.java
}
            @Override
            public String name() {
                return "default_on";
            }
        };
        FixedAutoscalingDeciderService defaultOff = new FixedAutoscalingDeciderService();
        AutoscalingCalculateCapacityService service = new AutoscalingCalculateCapacityService(Set.of(defaultOn, defaultOff));
        ClusterState state = ClusterState.builder(ClusterName.DEFAULT)
            .metadata(
                Metadata.builder()
                    .putCustom(
                        AutoscalingMetadata.NAME,
                        new AutoscalingMetadata(
                            new TreeMap<>(
                                Map.of("test", new AutoscalingPolicyMetadata(new AutoscalingPolicy("test", randomRoles(), new TreeMap<>())))
                            )
                        )
                    )
            )
            .build();
        assertThat(
            service.calculate(state, ClusterInfo.EMPTY, SnapshotShardSizeInfo.EMPTY, AutoscalingNodesInfo.EMPTY, () -> {})
                .get("test")
                .results()
                .keySet(),
            equalTo(Set.of(defaultOn.name()))
        );
    }
    private SortedMap<String, Settings> randomFixedDeciders() {