Fix silly rate bug (elastic#134826)

This change fixes a bug in the rate function where rows with values were 
incorrectly excluded instead of rows without values. Most of the metrics
in our tests are dense, so this issue was not detected.

Author: dnhatn

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

@@ -207,7 +207,7 @@ public final class Rate$Type$GroupingAggregatorFunction implements GroupingAggre
             Buffer buffer = null;
             for (int p = 0; p < groups.getPositionCount(); p++) {
                 int valuePosition = positionOffset + p;
-                if (valueBlock.isNull(valuePosition) == false) {
+                if (valueBlock.isNull(valuePosition)) {
                     continue;
                 }
                 assert valueBlock.getValueCount(valuePosition) == 1 : "expected single-valued block " + valueBlock;

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

@@ -22,6 +22,7 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 import java.util.function.Supplier;
 
 import static org.hamcrest.Matchers.equalTo;
@@ -85,6 +86,17 @@ private static TestCaseSupplier makeSupplier(TestCaseSupplier.TypedDataSupplier
         return new TestCaseSupplier(fieldSupplier.name(), List.of(type, DataType.DATETIME, DataType.INTEGER, DataType.LONG), () -> {
             TestCaseSupplier.TypedData fieldTypedData = fieldSupplier.get();
             List<Object> dataRows = fieldTypedData.multiRowData();
+            if (randomBoolean()) {
+                List<Object> withNulls = new ArrayList<>(dataRows);
+                for (Object dataRow : dataRows) {
+                    if (randomBoolean()) {
+                        withNulls.add(null);
+                    } else {
+                        withNulls.add(dataRow);
+                    }
+                }
+                dataRows = withNulls;
+            }
             fieldTypedData = TestCaseSupplier.TypedData.multiRow(dataRows, type, fieldTypedData.name());
             List<Long> timestamps = new ArrayList<>();
             List<Integer> slices = new ArrayList<>();
@@ -107,7 +119,7 @@ private static TestCaseSupplier makeSupplier(TestCaseSupplier.TypedDataSupplier
                 DataType.LONG,
                 "_max_timestamp"
             );
-
+            dataRows = dataRows.stream().filter(Objects::nonNull).toList();
             final Matcher<?> matcher;
             if (dataRows.size() < 2) {
                 matcher = Matchers.nullValue();