LayoutRestorer: Adjust panels are unchanged check (#103679)

adjust panels are unchanged check

public/app/features/dashboard-scene/scene/layouts-shared/LayoutRestorer.ts

@@ -28,6 +28,10 @@ export class LayoutRestorer {
  * Ideally we should check if persisted state is the same but not possible anymore with current serialization code that requires all panels be connected to a DashboardScene
  */
 function panelsAreUnchanged(a: VizPanel[], b: VizPanel[]) {
+  if (a.length < b.length) {
+    return false;
+  }
+
   for (let i = 0; i < a.length; i++) {
     const ap = a[i];
     const bp = b[i];