fix: DH-20036: Skip totalsConfig updates during model transitions to prevent stale column errors (#2645)

For DH-20036. Fixes a bug where removing a rollup group while keeping an
aggregation (like CountDistinct) causes an error.

Author: gzh2003

packages/iris-grid/src/IrisGridProxyModel.ts

@@ -11,7 +11,7 @@ import IrisGridTableModel from './IrisGridTableModel';
 import IrisGridPartitionedTableModel from './IrisGridPartitionedTableModel';
 import IrisGridTreeTableModel from './IrisGridTreeTableModel';
 import IrisGridModel from './IrisGridModel';
-import { type ColumnName } from './CommonTypes';
+import { type ColumnName, type UITotalsTableConfig } from './CommonTypes';
 import { isIrisGridTableModelTemplate } from './IrisGridTableModelTemplate';
 import {
   type PartitionConfig,
@@ -431,6 +431,15 @@ class IrisGridProxyModel extends IrisGridModel implements PartitionedGridModel {
     this.setNextModel(modelPromise);
   }
 
+  set totalsConfig(totalsConfig: UITotalsTableConfig | null) {
+    if (this.modelPromise != null) {
+      // Model switch in progress. Don't forward, as the config may reference stale columns.
+      // COLUMNS_CHANGED will reapply the correct config after.
+      return;
+    }
+    this.model.totalsConfig = totalsConfig;
+  }
+
   get isFilterRequired(): boolean {
     return this.originalModel.isFilterRequired;
   }