fix(query): delegate merge sort cardinality effect (#8532)

Signed-off-by: discord9 <discord9@163.com>

src/query/src/dist_plan/merge_sort.rs

@@ -21,6 +21,7 @@ use std::fmt;
 use std::sync::Arc;
 
 use datafusion::execution::TaskContext;
+use datafusion::physical_plan::execution_plan::CardinalityEffect;
 use datafusion::physical_plan::metrics::MetricsSet;
 use datafusion::physical_plan::projection::{ProjectionExec, make_with_child, update_ordering};
 use datafusion::physical_plan::sorts::sort::SortExec;
@@ -253,6 +254,10 @@ impl ExecutionPlan for MergeSortExec {
         self.inner.partition_statistics(partition)
     }
 
+    fn cardinality_effect(&self) -> CardinalityEffect {
+        self.inner.cardinality_effect()
+    }
+
     /// Intentionally keeps DataFusion's generic limit pushdown disabled.
     ///
     /// `MergeSortExec` still supports its own global fetch through