branch-2.1: [opt](Nereids) avoid generate nested alias expr when plan insert values (#50388)

fe/fe-core/src/main/java/org/apache/doris/nereids/rules/analysis/BindSink.java

@@ -247,6 +247,7 @@ public class BindSink implements AnalysisRuleFactory {
                 // we skip it.
                 continue;
             }
+            expr = expr.toSlot();
             DataType inputType = expr.getDataType();
             DataType targetType = DataType.fromCatalogType(tableSchema.get(i).getType());
             Expression castExpr = expr;