fix: disable truncate optimization for partition tables in DELETE (#23970) (#24016)

`DELETE FROM partition_table` (without WHERE clause) fails with:
```
ERROR 20101 (HY000): internal error: can not find table by id 0: accountId: 0
```

### Root Cause

MO has a truncate optimization that rewrites `DELETE FROM table` (no WHERE) into `DROP TABLE + CREATE TABLE`. This optimization does not check for partition tables. When applied to a partition table, the `TruncateTable` execution path iterates over `ForeignTbl` (which stores partition sub-table IDs), but for partition tables these IDs are 0-valued placeholders. The engine then calls `GetRelationById(0)`, which fails.

Two code paths needed the fix:
1. **New binder** (`bind_delete.go`): `canDeleteRewriteToTruncate()` was missing a partition table check
2. **Old builder fallback** (`build_dml_util.go`): `buildDeletePlans()` `canTruncate` condition was also missing the partition check

### Fix

Add `tableDef.Partition != nil` guard in both paths so partition tables are never rewritten to truncate. Instead, they follow the normal `PartitionDelete` operator path which correctly handles per-partition deletes.

### Changes

- `pkg/sql/plan/bind_delete.go`: Return `false` from `canDeleteRewriteToTruncate()` when `tableDef.Partition != nil`
- `pkg/sql/plan/build_dml_util.go`: Set `canTruncate = false` when `delCtx.tableDef.Partition != nil`

Approved by: @aunjgr, @ouyuanning

Author: robll-v1

pkg/sql/plan/bind_delete.go

@@ -48,7 +48,8 @@ func canDeleteRewriteToTruncate(ctx CompilerContext, dmlCtx *DMLContext) (bool,
 		if enabled && len(tableDef.RefChildTbls) > 0 ||
 			tableDef.ViewSql != nil ||
 			(dmlCtx.isClusterTable[i] && accountId != catalog.System_Account) ||
-			dmlCtx.objRefs[i].PubInfo != nil {
+			dmlCtx.objRefs[i].PubInfo != nil ||
+			tableDef.Partition != nil {
 			return false, nil
 		}
 	}

pkg/sql/plan/build_dml_util.go

@@ -414,7 +414,8 @@ func buildDeletePlans(ctx CompilerContext, builder *QueryBuilder, bindCtx *BindC
 	if enabled && len(delCtx.tableDef.RefChildTbls) > 0 ||
 		delCtx.tableDef.ViewSql != nil ||
 		(util.TableIsClusterTable(delCtx.tableDef.GetTableType()) && accountId != catalog.System_Account) ||
-		delCtx.objRef.PubInfo != nil || !deleteOptToTruncate {
+		delCtx.objRef.PubInfo != nil || !deleteOptToTruncate ||
+		delCtx.tableDef.Partition != nil {
 		canTruncate = false
 	}