fix(hgrid): Explicitly invoke detectChanges for the root grid #6860

Author: dkamburov

projects/igniteui-angular/src/lib/grids/hierarchical-grid/child-grid-row.component.ts

@@ -143,6 +143,7 @@ private resolver;
         this.hGrid.childRow =  this;
         // handler logic that re-emits hgrid events on the row island
         this.setupEventEmitters();
+        this.hGrid.rootGrid.cdr.detectChanges();
         this.layout.onGridCreated.emit({
             owner: this.layout,
             parentID: this.rowData.rowID,

projects/igniteui-angular/src/lib/grids/hierarchical-grid/hierarchical-grid.spec.ts

@@ -1372,10 +1372,8 @@ export class IgxHGridRemoteOnDemandComponent {
     }
 
     gridCreated(event: IGridCreatedEventArgs, rowIsland: IgxRowIslandComponent) {
-        setTimeout(() => {
-            event.grid.data = this.generateRowIslandData(5);
-            event.grid.cdr.detectChanges();
-        }, 1000);
+        event.grid.data = this.generateRowIslandData(5);
+        event.grid.cdr.detectChanges();
     }
 }