Remove excess code

Author: Raushen

packages/devextreme/js/__internal/grids/grid_core/ai_column/views/m_ai_column_view.ts

@@ -196,13 +196,4 @@ export const columnHeadersViewExtender = (
 
     super.renderDragCellContent($dragContainer, column);
   }
-
-  public dispose(): void {
-    super.dispose();
-    this.activeDropDownButtonInstance = null;
-
-    if (this.aiColumnOptionChangedHandler) {
-      this._columnsController.aiColumnOptionChanged.remove(this.aiColumnOptionChangedHandler);
-    }
-  }
 };

packages/devextreme/js/__internal/grids/grid_core/ai_column/views/m_ai_prompt_editor_view.ts

@@ -157,12 +157,4 @@ export class AIPromptEditorView extends View {
       // TODO: this.component.refresh();
     }
   }
-
-  public dispose(): void {
-    super.dispose();
-
-    if (this.aiColumnOptionChangedHandler) {
-      this.columnsController.aiColumnOptionChanged.remove(this.aiColumnOptionChangedHandler);
-    }
-  }
 }