[backport core/1.34] hotfix: stabilize flaky workflow sidebar browser tests (#7504)

Backport of #7280 to `core/1.34`

Automatically created by backport workflow.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7504-backport-core-1-34-hotfix-stabilize-flaky-workflow-sidebar-browser-tests-2ca6d73d3650810ab183d3f0e9316b70)
by [Unito](https://www.unito.io)

Co-authored-by: Johnpaul Chiwetelu <49923152+Myestery@users.noreply.github.com>
Co-authored-by: Terry Jia <terryjia88@gmail.com>
Co-authored-by: Alexander Brown <drjkl@comfy.org>
Co-authored-by: Luke Mino-Altherr <luke@comfy.org>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: GitHub Action <action@github.com>
Co-authored-by: Benjamin Lu <benjaminlu1107@gmail.com>

browser_tests/tests/sidebar/workflows.spec.ts

@@ -340,6 +340,11 @@ test.describe('Workflows sidebar', () => {
 
     await comfyPage.menu.workflowsTab.open()
 
+    // Wait for workflow to appear in Browse section after sync
+    const workflowItem =
+      comfyPage.menu.workflowsTab.getPersistedItem('workflow1.json')
+    await expect(workflowItem).toBeVisible({ timeout: 3000 })
+
     const nodeCount = await comfyPage.getGraphNodesCount()
 
     // Get the bounding box of the canvas element
@@ -358,6 +363,10 @@ test.describe('Workflows sidebar', () => {
       '#graph-canvas',
       { targetPosition }
     )
-    expect(await comfyPage.getGraphNodesCount()).toBe(nodeCount * 2)
+
+    // Wait for nodes to be inserted after drag-drop with retryable assertion
+    await expect
+      .poll(() => comfyPage.getGraphNodesCount(), { timeout: 3000 })
+      .toBe(nodeCount * 2)
   })
 })