[FTR]: revert table reference in DataGrid service getHeaderFields

ensures test order instead, as opened flyout contains a standalone datagrid the column header test assertion should happen on a state with only the first datagrid

test/functional/apps/context/_discover_navigation.ts

@@ -57,6 +57,11 @@ export default function ({ getService, getPageObjects }: FtrProviderContext) {
       await kibanaServer.uiSettings.replace({});
     });
 
+    it('should open the context view with the same columns', async () => {
+      const columnNames = await dataGrid.getHeaderFields();
+      expect(columnNames).to.eql(['@timestamp', ...TEST_COLUMN_NAMES]);
+    });
+
     it('should open the context view with the selected document as anchor and allows selecting next anchor', async () => {
       /**
        * Helper function to get the first timestamp of the document table
@@ -94,11 +99,6 @@ export default function ({ getService, getPageObjects }: FtrProviderContext) {
       });
     });
 
-    it('should open the context view with the same columns', async () => {
-      const columnNames = await dataGrid.getHeaderFields();
-      expect(columnNames).to.eql(['@timestamp', ...TEST_COLUMN_NAMES]);
-    });
-
     it('should open the context view with the filters disabled', async () => {
       let disabledFilterCounter = 0;
       for (const [columnName, value] of TEST_FILTER_COLUMN_NAMES) {

test/functional/services/data_grid.ts

@@ -384,8 +384,7 @@ export class DataGridService extends FtrService {
   }
 
   public async getHeaderFields(): Promise<string[]> {
-    const table = await this.find.byCssSelector('.euiDataGrid');
-    const result = await table.findAllByCssSelector(
+    const result = await this.find.allByCssSelector(
       '.euiDataGridHeaderCell:not(.euiDataGridHeaderCell--controlColumn) .euiDataGridHeaderCell__content'
     );