### Description

Only "search hits" based queries (no aggregations) provide a consistent view on the data when paginating through the result set. With point-in-time, it is possible to support transactional semantics for aggregation queries as well.

This issue is somewhat blocked by https://github.com/elastic/elasticsearch/issues/75528 because a PIT can not immediately be closed if the aggregation result set contains less than `fetch_size` records. This could cause some increased resource utilization due to open PITs. Especially if the client does not close the SQL cursor.
x-pack/plugin/sql/src/test/java/org/elasticsearch/xpack/sql/analysis/CancellationTests.java
verify(client).fieldCaps(any(), any());
        verify(client, times(1)).execute(eq(OpenPointInTimeAction.INSTANCE), any(), any());
        verify(client, times(1)).execute(eq(SearchAction.INSTANCE), any(), any());
        verify(client, times(1)).execute(eq(ClosePointInTimeAction.INSTANCE), any(), any());
        verify(client, times(1)).settings();
        verify(client, times(1)).threadPool();
        verifyNoMoreInteractions(client);
    }
    private ClusterService mockClusterService() {
        return mockClusterService(null);
    }
    private ClusterService mockClusterService(String nodeId) {
        final ClusterService mockClusterService = mock(ClusterService.class);
        final DiscoveryNode mockNode = mock(DiscoveryNode.class);
        final ClusterName mockClusterName = mock(ClusterName.class);
        when(mockNode.getId()).thenReturn(nodeId == null ? randomAlphaOfLength(10) : nodeId);
        when(mockClusterService.localNode()).thenReturn(mockNode);
        when(mockClusterName.value()).thenReturn(randomAlphaOfLength(10));
        when(mockClusterService.getClusterName()).thenReturn(mockClusterName);
        return mockClusterService;
    }
    private static IndexResolver indexResolver(Client client) {
        return new IndexResolver(client, randomAlphaOfLength(10), DefaultDataTypeRegistry.INSTANCE, Collections::emptySet);
    }
    private static SqlQueryTask randomTask() {
        return SqlTestUtils.randomTask(randomLong(), randomFrom(Mode.values()), SqlVersion.fromString("1.2.3"));
    }
}