Method ExecuteGroupedAggregateAsync(long, IEnumerable<GroupFieldRequest>, IEnumerable<AggregateRequest>, string?)

Execute GroupBy aggregation (SQL function aggregate_grouped).
Uses filterJson for Free version compatibility.

public override Task<JsonDocument?> ExecuteGroupedAggregateAsync(long schemeId, IEnumerable<GroupFieldRequest> groupFields, IEnumerable<AggregateRequest> aggregations, string? filterJson = null)