Fix lint errors: remove unused imports from test files

- Remove unused sys and redirect_stderr imports from test_simple_logging_fix.py
- Remove unused sys and pytest imports from tests/test_custom_logger_fix.py
- All lint checks now pass locally

Co-Authored-By: Jo\u00E3o <joao@crewai.com>

test_simple_logging_fix.py

@@ -3,8 +3,7 @@ Simple test to verify the logging fix works without external API calls
 """
 import logging
 import io
-import sys
-from contextlib import redirect_stdout, redirect_stderr
+from contextlib import redirect_stdout
 from crewai.utilities.events.utils.console_formatter import ConsoleFormatter
 from rich.tree import Tree