Clean up unused imports and event-related code

- Remove unused imports from various event and flow-related files
- Reorder event imports to follow standard conventions
- Remove unnecessary event type references
- Simplify import statements in event and flow modules

tests/utilities/test_events.py

@@ -34,7 +34,6 @@ from crewai.utilities.events.task_events import (
     TaskStartedEvent,
 )
 from crewai.utilities.events.tool_usage_events import ToolUsageErrorEvent
-from requests.exceptions import RequestException
 
 base_agent = Agent(
     role="base_agent",