[enhance](Nereids): delete output in olapscan toString() (#17288)

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/logical/LogicalOlapScan.java

@@ -180,7 +180,6 @@ public class LogicalOlapScan extends LogicalRelation implements CatalogRelation,
     public String toString() {
         return Utils.toSqlString("LogicalOlapScan",
                 "qualified", qualifiedName(),
-                "output", getOutput(),
                 "indexName", getSelectedMaterializedIndexName().orElse("<index_not_selected>"),
                 "selectedIndexId", selectedIndexId,
                 "preAgg", preAggStatus

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/physical/PhysicalOlapScan.java

@@ -111,7 +111,6 @@ public class PhysicalOlapScan extends PhysicalRelation implements OlapScan {
     public String toString() {
         return Utils.toSqlString("PhysicalOlapScan",
                 "qualified", Utils.qualifiedName(qualifier, olapTable.getName()),
-                "output", getOutput(),
                 "stats", statsDeriveResult
         );
     }

fe/fe-core/src/test/java/org/apache/doris/nereids/trees/plans/PlanToStringTest.java

@@ -82,7 +82,7 @@ public class PlanToStringTest {
         LogicalOlapScan plan = PlanConstructor.newLogicalOlapScan(0, "table", 0);
         Assertions.assertTrue(
                 plan.toString().matches("LogicalOlapScan \\( qualified=db\\.table, "
-                        + "output=\\[id#\\d+, name#\\d+], indexName=<index_not_selected>, "
+                        + "indexName=<index_not_selected>, "
                         + "selectedIndexId=-1, preAgg=ON \\)"));
     }