Bug 1678829 fix permafail due to pref change during render of about:preferences r=preferences-reviewers,ntim

Differential Revision: https://phabricator.services.mozilla.com/D99948

browser/components/preferences/tests/browser_search_subdialogs_within_preferences_1.js

@@ -13,8 +13,6 @@ add_task(async function() {
  * Test for searching for the "Set Home Page" subdialog.
  */
 add_task(async function() {
-  await openPreferencesViaOpenPreferencesAPI("paneHome", { leaveOpen: true });
-
   // Set custom URL so bookmark button will be shown on the page (otherwise it is hidden)
   await SpecialPowers.pushPrefEnv({
     set: [
@@ -23,6 +21,8 @@ add_task(async function() {
     ],
   });
 
+  await openPreferencesViaOpenPreferencesAPI("paneHome", { leaveOpen: true });
+
   // Wait for Activity Stream to add its panels
   await BrowserTestUtils.waitForCondition(() =>
     SpecialPowers.spawn(