Use Union for nav_factory type annotation

Replaces the use of the | operator with Union in the type annotation for nav_factory in test_navset_menu for improved compatibility and clarity.

Author: karangattu

tests/playwright/shiny/components/nav/navset_menu/test_app.py

@@ -1,5 +1,6 @@
 import pytest
 from playwright.sync_api import Page
+from typing import Union
 
 from shiny.playwright import controller
 from shiny.pytest import create_app_fixture
@@ -19,7 +20,7 @@
 def test_navset_menu(
     page: Page,
     app: ShinyAppProc,
-    nav_factory: type[controller.NavsetPill] | type[controller.NavsetUnderline],
+    nav_factory: Union[type[controller.NavsetPill], type[controller.NavsetUnderline]],
     nav_id: str,
     out_id: str,
 ):