Fix lint errors: remove unused imports

- Remove unused typing.Optional import
- Remove unused unittest.mock.MagicMock import
- Add noqa comment for necessary mlflow import in availability check

Co-Authored-By: João <joao@crewai.com>

tests/integrations/test_mlflow.py

@@ -1,7 +1,7 @@
 """Tests for MLFlow integration."""
 
 import pytest
-from unittest.mock import Mock, patch, MagicMock
+from unittest.mock import Mock, patch
 import sys