[opt](Nereids) fix several insert into related issues (#40467) (#40755)

pick from master #40467

- http_stream TVF should always generate one fragment plan
- http_stream TVF plan should not check root as scan node
- distinguish group_commit TVF with normal insert statement
- index and generate slot should based on type cast base slot
- agg_state could cast from nullable to non-nullable
- colocated and bucket scan range compute should only on scan node

fe/fe-common/src/main/java/org/apache/doris/catalog/Type.java

@@ -867,10 +867,6 @@ public abstract class Type {
                 return false;
             }
             for (int i = 0; i < sourceAggState.getSubTypes().size(); i++) {
-                // target subtype is not null but source subtype is nullable
-                if (!targetAggState.getSubTypeNullables().get(i) && sourceAggState.getSubTypeNullables().get(i)) {
-                    return false;
-                }
                 if (!canCastTo(sourceAggState.getSubTypes().get(i), targetAggState.getSubTypes().get(i))) {
                     return false;
                 }