chore: improve unsaved CSS styling code

Author: ghiscoding

src/app/examples/grid-composite-editor.component.ts

@@ -687,11 +687,11 @@ export class GridCompositeEditorComponent implements OnInit {
 
   renderUnsavedCellStyling(item: any, column: Column, editCommand: EditCommand) {
     if (editCommand && item && column) {
-      const row = this.angularGrid.dataView.getRowByItem(item) as number;
-      if (row >= 0) {
+      const row = this.angularGrid.dataView?.getRowByItem(item);
+      if (row !== undefined && row >= 0) {
         const hash = { [row]: { [column.id]: 'unsaved-editable-field' } };
         const cssStyleKey = `unsaved_highlight_${[column.id]}${row}`;
-        this.angularGrid.slickGrid.setCellCssStyles(`unsaved_highlight_${[column.id]}${row}`, hash);
+        this.angularGrid.slickGrid.setCellCssStyles(cssStyleKey, hash);
         this.cellCssStyleQueue.push(cssStyleKey);
       }
     }

src/app/modules/angular-slickgrid/components/angular-slickgrid.component.ts

@@ -582,7 +582,7 @@ export class AngularSlickgridComponent<TData = any> implements AfterViewInit, On
 
       // if you don't want the items that are not visible (due to being filtered out or being on a different page)
       // to stay selected, pass 'false' to the second arg
-      if (this.slickGrid?.getSelectionModel() && this.gridOptions && this.gridOptions.dataView && this.gridOptions.dataView.hasOwnProperty('syncGridSelection')) {
+      if (this.slickGrid?.getSelectionModel() && this.gridOptions?.dataView?.hasOwnProperty('syncGridSelection')) {
         // if we are using a Backend Service, we will do an extra flag check, the reason is because it might have some unintended behaviors
         // with the BackendServiceApi because technically the data in the page changes the DataView on every page change.
         let preservedRowSelectionWithBackend = false;