### Description

![image](https://github.com/elastic/elasticsearch/assets/76245/d0443170-0419-4759-b505-7620ff3d6594)

The execution time of grouping stats by multiple keywords has increased: 1.2 to 1.6 seconds (with doc_partitioning), 4.3 to 6.7 seconds (with shard_partitioning). The equivalent query with the _search API takes 1.8 seconds.

`from nyc_taxis | ... | stats c = count(dropoff_datetime) by trip_type, payment_type, vendor_id`

This regression occurred since July 2, 2023, and I suspect it may be due to the PR: [Support multivalued fields on arbitrary grouping](https://github.com/elastic/elasticsearch-internal/pull/1340).

/cc @nik9000
x-pack/plugin/esql/compute/src/test/java/org/elasticsearch/compute/operator/MultivalueDedupeTests.java
this.minDupsPerPosition = minDupsPerPosition;
        this.maxDupsPerPosition = maxDupsPerPosition;
    }
    public void testDedupeAdaptive() {
        BasicBlockTests.RandomBlock b = randomBlock();
        assertDeduped(b, MultivalueDedupe.dedupeToBlockAdaptive(Block.Ref.floating(b.block())));
    }
    public void testDedupeViaCopyAndSort() {
        BasicBlockTests.RandomBlock b = randomBlock();
        assertDeduped(b, MultivalueDedupe.dedupeToBlockUsingCopyAndSort(Block.Ref.floating(b.block())));
    }
    public void testDedupeViaCopyMissing() {
        BasicBlockTests.RandomBlock b = randomBlock();
        assertDeduped(b, MultivalueDedupe.dedupeToBlockUsingCopyMissing(Block.Ref.floating(b.block())));
    }
    private BasicBlockTests.RandomBlock randomBlock() {
        return BasicBlockTests.randomBlock(
            elementType,
            positionCount,
            nullAllowed,
            minValuesPerPosition,
            maxValuesPerPosition,
            minDupsPerPosition,
            maxDupsPerPosition
        );
    }
    private void assertDeduped(BasicBlockTests.RandomBlock b, Block.Ref deduped) {
        for (int p = 0; p < b.block().getPositionCount(); p++) {
            List<Object> v = b.values().get(p);
            Matcher<? extends Object> matcher = v == null