refactor(tests): Add strict type hints to fifth batch of test files

tests/test_gui2_events.py

@@ -1,11 +1,12 @@
 import pytest
 from unittest.mock import MagicMock, patch
+from typing import Generator
 from gui_2 import App
 import ai_client
 from events import EventEmitter
 
 @pytest.fixture
-def app_instance() -> None:
+def app_instance() -> Generator[type[App], None, None]:
  """
     Fixture to create an instance of the gui_2.App class for testing.
     It mocks functions that would render a window or block execution.
@@ -25,7 +26,7 @@ def app_instance() -> None:
  ):
   yield App
 
-def test_app_subscribes_to_events(app_instance):
+def test_app_subscribes_to_events(app_instance: type[App]) -> None:
  """
     This test checks that the App's __init__ method subscribes the necessary
     event handlers to the ai_client.events emitter.