[FIX] web: Correct notification service name in mocks

The service is called `notifications` when mocked in tests,
instead of `notification`

closes odoo/odoo#75859

Related: odoo/enterprise#20554
Signed-off-by: Vincent Schippefilt (vsc) <vsc@odoo.com>

addons/web/static/tests/helpers/mock_services.js

@@ -252,7 +252,7 @@ export const mocks = {
     cookie: () => fakeCookieService,
     effect: () => effectService, // BOI The real service ? Is this what we want ?
     localization: makeFakeLocalizationService,
-    notifications: makeFakeNotificationService,
+    notification: makeFakeNotificationService,
     router: makeFakeRouterService,
     rpc: makeFakeRPCService,
     title: () => fakeTitleService,