Bug 1704569 - Don't synthesize events on menus in...

Bug 1704569 - Don't synthesize events on menus in browser/components/search/test/browser/browser_oneOffContextMenu_setDefault.js. r=Gijs

Differential Revision: https://phabricator.services.mozilla.com/D111679

browser/components/search/test/browser/browser_oneOffContextMenu_setDefault.js

@@ -51,13 +51,14 @@ async function testSearchBarChangeEngine(win, testPrivate, isPrivateWindow) {
     TEST_ENGINE_NAME
   );
 
+  const contextMenu = searchOneOff.contextMenuPopup;
   const setDefaultEngineMenuItem = searchOneOff.querySelector(
     ".search-one-offs-context-set-default" + (testPrivate ? "-private" : "")
   );
 
   // Click the set default engine menu item.
   let promise = promiseDefaultEngineChanged(testPrivate);
-  EventUtils.synthesizeMouseAtCenter(setDefaultEngineMenuItem, {}, win);
+  contextMenu.activateItem(setDefaultEngineMenuItem);
 
   // This also checks the engine correctly changed.
   await promise;