fix(playwright): use domcontentloaded for saved-query nav to avoid CI timeout

The saved-query → SQL Lab navigation was timing out in CI because
waitUntil: 'load' blocks until all JS/CSS resources finish loading.
Switch to 'domcontentloaded' (DOM parsed, before subresources) and
bump timeout to API_RESPONSE (15s) since ensureEditorReady() already
handles full readiness downstream.

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

Author: sadpandajoe

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

@@ -238,8 +238,8 @@ test('saves a query and loads it from saved queries', async ({
   // 2. Saved-query API hydration (fires in useEffect after paint)
   await queryLink.click();
   await page.waitForURL(/sqllab/, {
-    waitUntil: 'load',
-    timeout: TIMEOUT.PAGE_LOAD,
+    waitUntil: 'domcontentloaded',
+    timeout: TIMEOUT.API_RESPONSE,
   });
   await waitForGet(page, `api/v1/saved_query/${savedQueryId}`, {
     timeout: TIMEOUT.API_RESPONSE,