fix: Resolve NameError and lint errors in crew_test.py

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

tests/crew_test.py

@@ -4,11 +4,9 @@ import hashlib
 import json
 import os
 import sys
-
 from concurrent.futures import Future
 from unittest import mock
-from unittest.mock import MagicMock, patch
-
+from unittest.mock import MagicMock, Mock, patch
 
 import pydantic_core
 import pytest
@@ -41,7 +39,6 @@ from crewai.utilities.events.event_listener import EventListener
 from crewai.utilities.rpm_controller import RPMController
 from crewai.utilities.task_output_storage_handler import TaskOutputStorageHandler
 
-
 # Skip streaming tests when running in CI/CD environments
 skip_streaming_in_ci = pytest.mark.skipif(
     os.getenv("CI") is not None, reason="Skipping streaming tests in CI/CD environments"