Fix flickering test: Use retry logic instead of fixed delays in custom-strategy test

Co-authored-by: Lipata <[email protected]>

Author: Copilot

projects/igniteui-angular-elements/src/app/custom-strategy.spec.ts

@@ -48,15 +48,31 @@ describe('Elements: ', () => {
             const columnEl = document.createElement("igc-column") as IgcNgElement;
             gridEl.appendChild(columnEl);
 
-            // TODO: Better way to wait - potentially expose the queue or observable for update on the strategy
-            await firstValueFrom(timer(10 /* SCHEDULE_DELAY */ * 2));
-
+            // Wait for both components to be fully initialized
             const gridComponent = (await gridEl.ngElementStrategy[ComponentRefKey]).instance as IgxGridComponent;
             const columnComponent = (await columnEl.ngElementStrategy[ComponentRefKey]).instance as IgxColumnComponent;
+
+            // Wait for the grid's columnList to contain the column component with retry logic
+            let retries = 0;
+            const maxRetries = 10;
+            const retryDelay = 10;
+            
+            while (retries < maxRetries && !gridComponent.columnList.toArray().includes(columnComponent)) {
+                await firstValueFrom(timer(retryDelay));
+                retries++;
+            }
+            
             expect(gridComponent.columnList.toArray()).toContain(columnComponent);
 
             columnEl.remove();
-            await firstValueFrom(timer(10 /* SCHEDULE_DELAY: DESTROY + QUERY */ * 3));
+            
+            // Wait for the column to be removed from the columnList with retry logic
+            retries = 0;
+            while (retries < maxRetries && gridComponent.columnList.toArray().includes(columnComponent)) {
+                await firstValueFrom(timer(retryDelay));
+                retries++;
+            }
+            
             expect(gridComponent.columnList.toArray()).toEqual([]);
         });