### 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
public void testMultiplePoliciesFixedCapacity() {
        AutoscalingCalculateCapacityService service = new AutoscalingCalculateCapacityService(Set.of(new FixedAutoscalingDeciderService()));
        Set<String> policyNames = IntStream.range(0, randomIntBetween(1, 10))
            .mapToObj(i -> "test_ " + randomAlphaOfLength(10))
            .collect(Collectors.toSet());
        SortedMap<String, AutoscalingPolicyMetadata> policies = new TreeMap<>(
            policyNames.stream()
                .map(s -> Tuple.tuple(s, new AutoscalingPolicyMetadata(new AutoscalingPolicy(s, randomRoles(), randomFixedDeciders()))))
                .collect(Collectors.toMap(Tuple::v1, Tuple::v2))
        );
        ClusterState state = ClusterState.builder(ClusterName.DEFAULT)
            .metadata(Metadata.builder().putCustom(AutoscalingMetadata.NAME, new AutoscalingMetadata(policies)))
            .build();
        SortedMap<String, AutoscalingDeciderResults> resultsMap = service.calculate(
            state,
            ClusterInfo.EMPTY,
            null,
            AutoscalingNodesInfo.EMPTY,
            () -> {}
        );
        assertThat(resultsMap.keySet(), equalTo(policyNames));
        for (Map.Entry<String, AutoscalingDeciderResults> entry : resultsMap.entrySet()) {
            AutoscalingDeciderResults results = entry.getValue();
            SortedMap<String, Settings> deciders = policies.get(entry.getKey()).policy().deciders();