fix(playwright): use toHaveURL for SPA navigation in saved-query test

The saved queries list uses React Router <Link>, which navigates via
history.pushState — no full page load occurs. page.waitForURL with
waitUntil hangs forever because domcontentloaded/load events never
re-fire on SPA transitions. Switch to expect(page).toHaveURL() which
polls the current URL instead of waiting for navigation events.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: sadpandajoe

superset-frontend/playwright/tests/sqllab/sqllab.spec.ts

@@ -237,10 +237,10 @@ test('saves a query and loads it from saved queries', async ({
   // 1. Full-page navigation (slow under CI load)
   // 2. Saved-query API hydration (fires in useEffect after paint)
   await queryLink.click();
-  await page.waitForURL(/sqllab/, {
-    waitUntil: 'domcontentloaded',
-    timeout: TIMEOUT.API_RESPONSE,
-  });
+  // React Router <Link> triggers a SPA navigation (history.pushState), not a
+  // full page load, so page.waitForURL with waitUntil would hang forever.
+  // Use toHaveURL which polls the current URL instead.
+  await expect(page).toHaveURL(/sqllab/, { timeout: TIMEOUT.API_RESPONSE });
   await waitForGet(page, `api/v1/saved_query/${savedQueryId}`, {
     timeout: TIMEOUT.API_RESPONSE,
   });