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

tests/verify_mma_gui_robust.py

@@ -1,4 +1,3 @@
-
 import subprocess
 import time
 import sys
@@ -14,8 +13,8 @@ from api_hook_client import ApiHookClient
 
 class TestMMAGUIRobust(unittest.TestCase):
  @classmethod
- def setUpClass(cls):
- # 1. Launch gui_2.py with --enable-test-hooks
+ def setUpClass(cls) -> None:
+  # 1. Launch gui_2.py with --enable-test-hooks
   cls.gui_command = [sys.executable, "gui_2.py", "--enable-test-hooks"]
   print(f"Launching GUI: {' '.join(cls.gui_command)}")
   cls.gui_process = subprocess.Popen(