**Build scan:**
https://gradle-enterprise.elastic.co/s/whiwuz23mtmvq/tests/:x-pack:plugin:rollup:test/org.elasticsearch.xpack.rollup.v2.RollupActionSingleNodeTests/testCannotRollupToExistingIndex

**Reproduction line:**
`./gradlew ':x-pack:plugin:rollup:test' --tests "org.elasticsearch.xpack.rollup.v2.RollupActionSingleNodeTests.testCannotRollupToExistingIndex" -Dtests.seed=9814B01249EAC77D -Dtests.locale=en-SG -Dtests.timezone=Africa/Windhoek -Druntime.java=17`

**Applicable branches:**
main

**Reproduces locally?:**
Didn't try

**Failure history:**
https://gradle-enterprise.elastic.co/scans/tests?tests.container=org.elasticsearch.xpack.rollup.v2.RollupActionSingleNodeTests&tests.test=testCannotRollupToExistingIndex

**Failure excerpt:**
```
org.elasticsearch.index.IndexNotFoundException: no such index [rollup-testcannotrollupwhileotherrollupinprogress-svlo]

  at __randomizedtesting.SeedInfo.seed([9814B01249EAC77D:325B86553CE92325]:0)
  at org.elasticsearch.cluster.metadata.Metadata.getIndexSafe(Metadata.java:919)
  at org.elasticsearch.cluster.metadata.MetadataDeleteIndexService.deleteIndices(MetadataDeleteIndexService.java:89)
  at org.elasticsearch.cluster.metadata.MetadataDeleteIndexService$1.execute(MetadataDeleteIndexService.java:70)
  at org.elasticsearch.cluster.service.MasterService$UnbatchedExecutor.execute(MasterService.java:515)
  at org.elasticsearch.cluster.service.MasterService.innerExecuteTasks(MasterService.java:959)
  at org.elasticsearch.cluster.service.MasterService.executeTasks(MasterService.java:929)
  at org.elasticsearch.cluster.service.MasterService.runTasks(MasterService.java:261)
  at org.elasticsearch.cluster.service.MasterService$Batcher.run(MasterService.java:165)
  at org.elasticsearch.cluster.service.TaskBatcher.runIfNotProcessed(TaskBatcher.java:110)
  at org.elasticsearch.cluster.service.TaskBatcher$BatchedTask.run(TaskBatcher.java:148)
  at org.elasticsearch.common.util.concurrent.ThreadContext$ContextPreservingRunnable.run(ThreadContext.java:710)
  at org.elasticsearch.common.util.concurrent.PrioritizedEsThreadPoolExecutor$TieBreakingPrioritizedRunnable.runAndClean(PrioritizedEsThreadPoolExecutor.java:257)
  at org.elasticsearch.common.util.concurrent.PrioritizedEsThreadPoolExecutor$TieBreakingPrioritizedRunnable.run(PrioritizedEsThreadPoolExecutor.java:223)
  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
  at java.lang.Thread.run(Thread.java:833)

```
x-pack/plugin/rollup/src/test/java/org/elasticsearch/xpack/rollup/v2/RollupActionSingleNodeTests.java
.stream()
            .filter(entry -> labelFields.containsKey(entry.getKey()))
            .toList());
        List<Map.Entry<String, String>> labelFieldSourceIndexProperties = (sourceIndexCloneProperties.entrySet()
            .stream()
            .filter(entry -> labelFields.containsKey(entry.getKey()))
            .toList());
        assertEquals(labelFieldRollupIndexCloneProperties, labelFieldSourceIndexProperties);
    }
    private void assertRollupIndexAggregations(
        String sourceIndex,
        String rollupIndex,
        RollupActionConfig config,
        Map<String, TimeSeriesParams.MetricType> metricFields,
        Map<String, String> labelFields
    ) {
        final AggregationBuilder aggregations = buildAggregations(config, metricFields, labelFields, config.getTimestampField());
        Aggregations origResp = aggregate(sourceIndex, aggregations);
        Aggregations rollupResp = aggregate(rollupIndex, aggregations);
        assertEquals(origResp.asMap().keySet(), rollupResp.asMap().keySet());
        StringTerms originalTsIdTermsAggregation = (StringTerms) origResp.getAsMap().values().stream().toList().get(0);
        StringTerms rollupTsIdTermsAggregation = (StringTerms) rollupResp.getAsMap().values().stream().toList().get(0);
        originalTsIdTermsAggregation.getBuckets().forEach(originalBucket -> {
            StringTerms.Bucket rollupBucket = rollupTsIdTermsAggregation.getBucketByKey(originalBucket.getKeyAsString());
            assertEquals(originalBucket.getAggregations().asList().size(), rollupBucket.getAggregations().asList().size());
            InternalDateHistogram originalDateHistogram = (InternalDateHistogram) originalBucket.getAggregations().asList().get(0);
            InternalDateHistogram rollupDateHistogram = (InternalDateHistogram) rollupBucket.getAggregations().asList().get(0);
            List<InternalDateHistogram.Bucket> originalDateHistogramBuckets = originalDateHistogram.getBuckets();
            List<InternalDateHistogram.Bucket> rollupDateHistogramBuckets = rollupDateHistogram.getBuckets();
            assertEquals(originalDateHistogramBuckets.size(), rollupDateHistogramBuckets.size());