### CI Link

https://gradle-enterprise.elastic.co/s/pzjicoqh7nuhq

### Repro line

./gradlew ':server:internalClusterTest' --tests "org.elasticsearch.snapshots.BlobStoreIncrementalityIT.testRecordCorrectSegmentCountsWithBackgroundMerges" -Dtests.seed=DEA1040A4A18200C -Dtests.locale=ar-KW -Dtests.timezone=Etc/Universal -Druntime.java=17

### Does it reproduce?

Yes

### Applicable branches

main, 8.4

### Failure history

First time it fails in the last 7 days: https://gradle-enterprise.elastic.co/scans/tests?search.timeZoneId=Europe/Bucharest&tests.container=org.elasticsearch.snapshots.BlobStoreIncrementalityIT&tests.test=testRecordCorrectSegmentCountsWithBackgroundMerges

### Failure excerpt

```
org.elasticsearch.snapshots.BlobStoreIncrementalityIT > testRecordCorrectSegmentCountsWithBackgroundMerges FAILED
    java.lang.AssertionError: 
    Expected: a value less than <3L>
         but: <3L> was equal to <3L>
        at __randomizedtesting.SeedInfo.seed([DEA1040A4A18200C:C81912C0892C8B7B]:0)
        at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:18)
        at org.junit.Assert.assertThat(Assert.java:956)
        at org.junit.Assert.assertThat(Assert.java:923)
        at org.elasticsearch.snapshots.BlobStoreIncrementalityIT.lambda$testRecordCorrectSegmentCountsWithBackgroundMerges$0(BlobStoreIncrementalityIT.java:236)
        at org.elasticsearch.test.ESTestCase.assertBusy(ESTestCase.java:1104)
        at org.elasticsearch.snapshots.BlobStoreIncrementalityIT.testRecordCorrectSegmentCountsWithBackgroundMerges(BlobStoreIncrementalityIT.java:234)
```
server/src/internalClusterTest/java/org/elasticsearch/snapshots/BlobStoreIncrementalityIT.java
public class BlobStoreIncrementalityIT extends AbstractSnapshotIntegTestCase {
    @Override
    protected Collection<Class<? extends Plugin>> nodePlugins() {
        return CollectionUtils.appendToCopy(super.nodePlugins(), InternalSettingsPlugin.class);
    }
    public void testIncrementalBehaviorOnPrimaryFailover() throws InterruptedException, ExecutionException, IOException {
        internalCluster().startMasterOnlyNode();
        final String primaryNode = internalCluster().startDataOnlyNode();
        final String indexName = "test-index";
        createIndex(
            indexName,
            Settings.builder()
                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
                .put(UnassignedInfo.INDEX_DELAYED_NODE_LEFT_TIMEOUT_SETTING.getKey(), 0)
                .build()
        );
        ensureYellow(indexName);
        final String newPrimary = internalCluster().startDataOnlyNode();
        final Collection<String> toDelete = new ArrayList<>();
        ensureGreen(indexName);
        logger.info("--> adding some documents to test index");
        for (int j = 0; j < randomIntBetween(1, 10); ++j) {
            final BulkRequest bulkRequest = new BulkRequest();