Update android codelab code to fix linter errors

doc/android-guide.md

@@ -75,6 +75,8 @@ Create a new Avatar test class file `codelab_test.py` in the Android Avatar
 tests folder, `packages/modules/Bluetooth/android/pandora/test/`:
 
 ```python
+import asyncio # Provides utilities for calling asynchronous functions.
+
 from typing import Optional  # Avatar is strictly typed.
 
 # Importing Mobly modules required for the test.
@@ -90,7 +92,7 @@ from pandora.host_pb2 import RANDOM, DataTypes
 
 
 # The test class to test the LE (Bluetooth Low Energy) Connectivity.
-class CodelabTest(base_test.BaseTestClass):
+class CodelabTest(base_test.BaseTestClass): # type: ignore[misc]
     devices: Optional[PandoraDevices] = None
     dut: PandoraClient
     ref: BumblePandoraClient  # `BumblePandoraClient` is a sub-class of `PandoraClient`