[fix](Nereids) npe when delete with cte and without using (#39379)

fe/fe-core/src/main/java/org/apache/doris/nereids/parser/LogicalPlanBuilder.java

@@ -960,7 +960,9 @@ public LogicalPlan visitDelete(DeleteContext ctx) {
                     partitionSpec.second, query);
         } else {
             // convert to insert into select
-            query = withRelations(query, ctx.relations().relation());
+            if (ctx.USING() != null) {
+                query = withRelations(query, ctx.relations().relation());
+            }
             query = withFilter(query, Optional.ofNullable(ctx.whereClause()));
             Optional<LogicalPlan> cte = Optional.empty();
             if (ctx.cte() != null) {

regression-test/suites/nereids_p0/delete/delete_cte.groovy

@@ -113,6 +113,9 @@ suite('nereids_delete_cte') {
             """
 
             qt_sql "select * from ${t1} order by id, id1"
+
+            // test cte != null and using == null
+            sql """with cte as (select 1) delete from ${t1} where ${t1}.id = 100"""
         }
     }
 }