fix: tests and linters

tests/test_shutdown_voice_cleanup.py

@@ -16,6 +16,7 @@ class ShutdownVoiceCleanupTests(unittest.IsolatedAsyncioTestCase):
         self.uploads = MagicMock()
         self.config = MagicMock()
         self.history = MagicMock()
+        self.migration = MagicMock()
 
         self.bot = MusicBot(
             self.settings,
@@ -23,6 +24,7 @@ class ShutdownVoiceCleanupTests(unittest.IsolatedAsyncioTestCase):
             self.uploads,
             self.config,
             self.history,
+            self.migration,
         )
         self.player = MagicMock()
         self.bot.player = self.player