Fixes countDistinctWithConditions in csv-spec tests (elastic#135097)

Author: ncordon

docs/changelog/135097.yaml

@@ -0,0 +1,6 @@
+pr: 135097
+summary: Fixes `countDistinctWithConditions` in csv-spec tests
+area: ES|QL
+type: bug
+issues:
+  - 134380

x-pack/plugin/esql/qa/testFixtures/src/main/resources/stats.csv-spec

@@ -3255,7 +3255,6 @@ required_capability: stats_with_filtered_surrogate_fixed
 
 ROW x = [1, 2, 3, 4, 5]
 | MV_EXPAND x
-| EVAL agg_metric = TO_AGGREGATE_METRIC_DOUBLE(x)
 | STATS count1 = COUNT_DISTINCT(x) WHERE x <= 3,
         count2 = COUNT_DISTINCT(x),
         count3 = COUNT_DISTINCT(1) WHERE x <= 3,