DataGrid: simplify first-cell class update logic (T1318812)

- Remove needToUpdateFirstCellClasses check from adaptivity resizing
- Remove showColumnLines gate from column headers _createCell
- Remove needToUpdateFirstCellClasses method from ColumnsView

Author: Alyar

packages/devextreme/js/__internal/grids/grid_core/adaptivity/m_adaptivity.ts

@@ -1326,7 +1326,7 @@ const resizing = (Base: ModuleType<ResizingController>) => class AdaptivityResiz
       COLUMN_VIEWS.forEach((viewName) => {
         const view = this.getView(viewName);
 
-        if (view?.isVisible() && view?.needToUpdateFirstCellClasses()) {
+        if (view?.isVisible()) {
           view.updateFirstCellClasses();
         }
       });

packages/devextreme/js/__internal/grids/grid_core/column_headers/m_column_headers.ts

@@ -359,15 +359,14 @@ export class ColumnHeadersView extends ColumnContextMenuMixin(ColumnsView) {
     const { column } = options;
     // @ts-expect-error
     const $cellElement = super._createCell.apply(this, arguments);
-    const showColumnLines = this.option('showColumnLines');
 
     if (options.rowType !== 'header') {
       return $cellElement;
     }
 
     const rowCount = this.getRowCount();
 
-    if (!showColumnLines && rowCount > 1) {
+    if (rowCount > 1) {
       this.toggleFirstCellClass(
         $cellElement,
         this._columnsController.isFirstColumn(column, options.rowIndex),

packages/devextreme/js/__internal/grids/grid_core/views/m_columns_view.ts

@@ -1516,13 +1516,6 @@ export class ColumnsView extends ColumnStateMixin(modules.View) {
     $dragContainer.text(column.caption ?? '');
   }
 
-  public needToUpdateFirstCellClasses(): boolean {
-    const hasHidingColumnsQueue = !!this._adaptiveColumnsController
-      ?.getHidingColumnsQueue()?.length;
-
-    return hasHidingColumnsQueue;
-  }
-
   public updateFirstCellClasses(): void {
     const rows = this._getRows();