Fix empty VALUES with ordinals grouping (elastic#130861)

We should not build the sorted structure for the ordinal grouping
operator if the requested position is larger than maxGroupId. This
situation occurs with nulls. We should benchmark the ordinal blocks and
consider removing the ordinal grouping operator if performance is
similar; otherwise, we need to integrate this operator with
GroupingAggregatorFunctionTestCase.

Relates elastic#130576

(cherry picked from commit f58d291)

Author: dnhatn

x-pack/plugin/esql/compute/src/main/generated-src/org/elasticsearch/compute/aggregation/ValuesBytesRefAggregator.java

@@ -104,10 +104,10 @@ $endif$
     }
 
     public static void combineStates(GroupingState current, int currentGroupId, GroupingState state, int statePosition) {
-        var sorted = state.sortedForOrdinalMerging(current);
         if (statePosition > state.maxGroupId) {
             return;
         }
+        var sorted = state.sortedForOrdinalMerging(current);
         var start = statePosition > 0 ? sorted.counts[statePosition - 1] : 0;
         var end = sorted.counts[statePosition];
         for (int i = start; i < end; i++) {