Dashboard: Fixes blank / empty panels after duplicate and add library panel (#35906) (#35924)

(cherry picked from commit 333932812d)

Co-authored-by: Torkel Ödegaard <torkel@grafana.org>

public/app/features/dashboard/dashgrid/DashboardGrid.tsx

@@ -162,11 +162,7 @@ export class DashboardGrid extends PureComponent<Props, State> {
     }
 
     this.props.dashboard.sortPanelsByGridPos();
-
-    // onLayoutChange is called onMount this marks layout as initialized and we are ready to render panels
-    if (!this.state.isLayoutInitialized) {
-      this.setState({ isLayoutInitialized: true });
-    }
+    this.forceUpdate();
   };
 
   triggerForceUpdate = () => {