### CI Link

https://gradle-enterprise.elastic.co/s/7dleq35dp5stm

### Repro line

./gradlew ':x-pack:plugin:core:test' --tests "org.elasticsearch.xpack.core.ilm.SetSingleNodeAllocateStepTests.testPerformActionAttrsRequestFails" -Dtests.seed=6B438F3C3DADE5D2 -Dtests.locale=nl -Dtests.timezone=Asia/Chongqin

### Does it reproduce?

Yes

### Applicable branches

8.1, 8.0

### Failure history

Seems to fail rarely, but has failed before. Example: https://gradle-enterprise.elastic.co/s/d33b4fzn7yoh6

### Failure excerpt

```
org.elasticsearch.xpack.core.ilm.SetSingleNodeAllocateStepTests > testPerformActionAttrsRequestFails FAILED
    java.lang.AssertionError: Node roles must not be provided as attributes but saw attributes {ml=K}
        at __randomizedtesting.SeedInfo.seed([C679BACC1DA27FA7:CB16887322D9C088]:0)
        at org.elasticsearch.cluster.node.DiscoveryNode.<init>(DiscoveryNode.java:233)
        at org.elasticsearch.cluster.node.DiscoveryNode.<init>(DiscoveryNode.java:175)
```
x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ilm/SetSingleNodeAllocateStepTests.java
Set<String> validNodeIds,
        DiscoveryNodes nodes,
        IndexRoutingTable indexRoutingTable
    ) throws Exception {
        ImmutableOpenMap.Builder<String, IndexMetadata> indices = ImmutableOpenMap.<String, IndexMetadata>builder()
            .fPut(index.getName(), indexMetadata);
        ClusterState clusterState = ClusterState.builder(ClusterState.EMPTY_STATE)
            .metadata(Metadata.builder().indices(indices.build()))
            .nodes(nodes)
            .routingTable(RoutingTable.builder().add(indexRoutingTable).build())
            .build();
        SetSingleNodeAllocateStep step = createRandomInstance();
        Mockito.doAnswer(invocation -> {
            UpdateSettingsRequest request = (UpdateSettingsRequest) invocation.getArguments()[0];
            @SuppressWarnings("unchecked")
            ActionListener<AcknowledgedResponse> listener = (ActionListener<AcknowledgedResponse>) invocation.getArguments()[1];
            assertSettingsRequestContainsValueFrom(
                request,
                IndexMetadata.INDEX_ROUTING_REQUIRE_GROUP_SETTING.getKey() + "_id",
                validNodeIds,
                true,
                indexMetadata.getIndex().getName()
            );
            listener.onResponse(AcknowledgedResponse.TRUE);
            return null;
        }).when(indicesClient).updateSettings(Mockito.any(), Mockito.any());
        PlainActionFuture.<Void, Exception>get(f -> step.performAction(indexMetadata, clusterState, null, f));
        Mockito.verify(client, Mockito.only()).admin();
        Mockito.verify(adminClient, Mockito.only()).indices();
        Mockito.verify(indicesClient, Mockito.only()).updateSettings(Mockito.any(), Mockito.any());