fix: resolve lint issues in human input event streaming implementation

- Remove unused imports from server modules and test files
- Fix undefined variable references in test assertions
- All ruff checks now pass locally

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

tests/server/test_event_stream_manager.py

@@ -1,10 +1,7 @@
-import pytest
-import asyncio
-import json
 from unittest.mock import MagicMock, patch
 
 from crewai.server.event_stream_manager import EventStreamManager
-from crewai.utilities.events.task_events import HumanInputRequiredEvent, HumanInputCompletedEvent
+from crewai.utilities.events.task_events import HumanInputRequiredEvent
 
 
 class TestEventStreamManager:

tests/server/test_human_input_server.py

@@ -1,7 +1,4 @@
 import pytest
-import asyncio
-import json
-from unittest.mock import patch, MagicMock
 
 try:
     from fastapi.testclient import TestClient