Address CI failures and code review feedback

- Remove unused pytest imports from test files (fixes lint errors)
- Fix CodeQL security alert by using exact URL validation instead of substring check
- Enhance SSL function documentation with detailed environment variable precedence
- Improve error handling in fetch_provider_data with current CA bundle path display
- Add more helpful guidance for SSL certificate configuration issues

Addresses feedback from AI code review and resolves CI lint/security failures.

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

tests/cli/test_provider_ssl.py

@@ -3,7 +3,6 @@ import tempfile
 from pathlib import Path
 from unittest.mock import Mock, patch
 
-import pytest
 import requests
 
 from crewai.cli.provider import fetch_provider_data, get_ssl_verify_config